So... Let me preface that usually my predictions for upcoming Apple products turn out to be wrong... 
But, I have some thoughts I'd like to share, based on what we now know:
Apple will want to limit the amount of different CPU versions, which is quite obvious in their current iPhone/iPad lineup, as well as the Mac's released this week (all using the same chip). This makes it easier to predict what will happen with future Apple Silicon products, I think.
M1 is clearly the replacement for i3. It is for low-end Macs, such as Macbook Air, low-end Mac Mini, and low-end Macbook Pro. Who knows, it may end up in a low-end iMac too.
A14 is the mainstream processor for mobile, it is in all 4 new iPhones, AND in iPad Air.
We have been wondering why iPad Pro is still stuck with an older CPU (in reality, two generations old). My guess is that Apple will kill the A(number)X/Z nomenclature for the iPad Pro variant, and instead simply put the M1 in the iPad Pro. It has the "A14" cores, and the limited RAM/I/O makes sense for iPad Pro. iPad Pro with USB C needs the USB C controller in the M1 - the iPhone/iPads with Lightning connectors do not.
Next year, we will see a higher-end version of M-processor - let's call it "M2". It may or may not be launched before the A15 for iPhone/iPad, but regardless, it will share the same cores as A15, which are updated from A14/M1. This will replace the i5/i7/i9 products. It will include more CPU cores, my guess is 12 which would be more than any current Macbook Pro or iMac - which are the products where it will be used. The M1 has now taken the heat of the first generation issues, and the "M2" will be launched in redesigned Macbook Pro's (14 and 16 inches?), and redesigned iMacs (24 inches?). The "M2" will include 12-16 GPU cores, which including updates to the cores itself will provide at least double the GPU performance of M1. This will enable it to replace all but the highest end external GPU's in the current lineup, and the new Macbook Pro/iMacs may not even provide external graphics as an option - the argument being, you don't need it. The "M2" will provide higher RAM and I/O capability, such as up to 64 GB RAM. "M2" will be provided as an option for higher-end Mac Mini, but not for Macbook Air. We may see an "entry Mac Mini" using fanless M1 in an Apple TV-style case - but this is a longshot, as it may be too cheap for Apple's revenue... I could definitely see them killing the small Macbook Pro though, as the Macbook Air is awfully close now.
In 2022, we will see an "M-Pro" CPU using "A16" level cores, with pro features such as support for very high amounts of ECC RAM, extensive I/O, external graphics, high Core count, etc. Like a Xeon, this will be less efficient than the "standard" chips. This will be used in iMac Pro and Mac Pro, which may be the only products to support external graphics.
In summary:
A-level processors used in standard mobile level products: iPhone, iPad, Apple TV
"M1" used in low-power scenarios: iPad Pro, Macbook Air, entry-level iMac and entry-level Mac Mini
"M2" used in mid-level scenarios: Macbook Pro, Higher-end iMac, higher-end Mac Mini
"M-Pro" used in high-end/Pro products: iMac Pro and Mac Pro
I will argue this would make for a very clean and user friendly lineup of products, with clear distinctions worth upgrading to, without leaving the standard versions as dogs. I'm debating with myself over how often I think they will update the CPU's. On one hand, I wouldn't put it past Apple to skip a generation here and there, on the other hand they will want to use the same core in as many chips as possible to maximize benefits of mass production. So yearly updates to CPU's across the board, with no other changes, might make sense logistically. Updates to the cores every year (perhaps save the Pro version), with old version used in entry-level models, sounds quite Apple-y to me... So over time, rather than using "M1" in the low-end Macbook Pro and iMac for instance, you would get last years "M2", because that one will have the RAM/IO support needed for the hardware platform. Either that, or they always use current version, and offer both "M1" and "M2" in the same product... See, I told you I was debating with myself
But, I have some thoughts I'd like to share, based on what we now know:Apple will want to limit the amount of different CPU versions, which is quite obvious in their current iPhone/iPad lineup, as well as the Mac's released this week (all using the same chip). This makes it easier to predict what will happen with future Apple Silicon products, I think.
M1 is clearly the replacement for i3. It is for low-end Macs, such as Macbook Air, low-end Mac Mini, and low-end Macbook Pro. Who knows, it may end up in a low-end iMac too.
A14 is the mainstream processor for mobile, it is in all 4 new iPhones, AND in iPad Air.
We have been wondering why iPad Pro is still stuck with an older CPU (in reality, two generations old). My guess is that Apple will kill the A(number)X/Z nomenclature for the iPad Pro variant, and instead simply put the M1 in the iPad Pro. It has the "A14" cores, and the limited RAM/I/O makes sense for iPad Pro. iPad Pro with USB C needs the USB C controller in the M1 - the iPhone/iPads with Lightning connectors do not.
Next year, we will see a higher-end version of M-processor - let's call it "M2". It may or may not be launched before the A15 for iPhone/iPad, but regardless, it will share the same cores as A15, which are updated from A14/M1. This will replace the i5/i7/i9 products. It will include more CPU cores, my guess is 12 which would be more than any current Macbook Pro or iMac - which are the products where it will be used. The M1 has now taken the heat of the first generation issues, and the "M2" will be launched in redesigned Macbook Pro's (14 and 16 inches?), and redesigned iMacs (24 inches?). The "M2" will include 12-16 GPU cores, which including updates to the cores itself will provide at least double the GPU performance of M1. This will enable it to replace all but the highest end external GPU's in the current lineup, and the new Macbook Pro/iMacs may not even provide external graphics as an option - the argument being, you don't need it. The "M2" will provide higher RAM and I/O capability, such as up to 64 GB RAM. "M2" will be provided as an option for higher-end Mac Mini, but not for Macbook Air. We may see an "entry Mac Mini" using fanless M1 in an Apple TV-style case - but this is a longshot, as it may be too cheap for Apple's revenue... I could definitely see them killing the small Macbook Pro though, as the Macbook Air is awfully close now.
In 2022, we will see an "M-Pro" CPU using "A16" level cores, with pro features such as support for very high amounts of ECC RAM, extensive I/O, external graphics, high Core count, etc. Like a Xeon, this will be less efficient than the "standard" chips. This will be used in iMac Pro and Mac Pro, which may be the only products to support external graphics.
In summary:
A-level processors used in standard mobile level products: iPhone, iPad, Apple TV
"M1" used in low-power scenarios: iPad Pro, Macbook Air, entry-level iMac and entry-level Mac Mini
"M2" used in mid-level scenarios: Macbook Pro, Higher-end iMac, higher-end Mac Mini
"M-Pro" used in high-end/Pro products: iMac Pro and Mac Pro
I will argue this would make for a very clean and user friendly lineup of products, with clear distinctions worth upgrading to, without leaving the standard versions as dogs. I'm debating with myself over how often I think they will update the CPU's. On one hand, I wouldn't put it past Apple to skip a generation here and there, on the other hand they will want to use the same core in as many chips as possible to maximize benefits of mass production. So yearly updates to CPU's across the board, with no other changes, might make sense logistically. Updates to the cores every year (perhaps save the Pro version), with old version used in entry-level models, sounds quite Apple-y to me... So over time, rather than using "M1" in the low-end Macbook Pro and iMac for instance, you would get last years "M2", because that one will have the RAM/IO support needed for the hardware platform. Either that, or they always use current version, and offer both "M1" and "M2" in the same product... See, I told you I was debating with myself
