But if apple would adopt the iMP chassis for the iMac, why would they do it now in 2020 instead of last year's refresh...?
Exactly this...Why wouldn't they do it in last year's refresh. It seemed like no brainer. Especially after the introduction of the Mac Pro. I don't really see the purpose of a pro iMac when you already have Mac Pro at the same time.
Well. I say the iMac Pro 'chassis' which...is really...the 'iMac' chassis with some better cooling and a paint job. Let's be more precise here. One of those 'cost' items is on the 'cheaper' (no k/b, no mouse, no dGPU, no monitor...) Mac Mini. And the superior cooling? How much does that actually cost? Three years later the 'oven bake' iMacs could do with better cooling. But, yes. That will come down to unit cost and how much that adds to the iMac price or whether that (3 years later) it can be absorbed into the iMac's cost.
Short answer: Cost.
Short answer: 2019? Too soon. (See above, 'Cost.')
Short answer: 2020. Time is right. (See above. 'Cost.' When the unit cost is low enough to fit inside Apple's R&D and margins for profit for the iMac pricing. Alongside all the other improvements which will follow the same formula for Apple's margins. When the price to buy these things is negliable in difference we'll get a boost in specs at the same price or if they cost more apple passes on the cost to the customer and also, occasionally takes the pish and charges what they like. See socks, wheels and monitor stands. They're rich enough not to care whether people like those prices or not. It's an ugly side to them. That's why I stopped iphone, ipad buying every year. They kept increasing prices.)
Apple will double the amount of SSD or standard ram when there is no material cost difference to itself and that aligns with the customer after Apple gets its margins 1st.
And certainly in terms of SSD, there's no much difference between 128, 256 and 512 gig SSDs for me. Let alone a company like apple that should be offering the best product for the best price. So. The mini got 'bumped.' (On an otherwise apologetic 'update.')
Likewise. When the cost of the cooling on the iMac Pro R&D is ammortised through time then it will become available. Perhaps. (Can't say for definite. It's not here yet.) But it 'should' as cooling on the iMac is it's Achilles heel.
What seems like No brainers to us crash upon the rocks of Apple's R&D, Margins, Marketing and upsell policy politics. (Not that I like some of those things. ie. Selling 3 year old machines with no price cut. Letting the Mac Pro rot for 6 years. Seeling $700 wheels. C'mon...)
The iMac Pro was the easiest stop gap whilst they pregnant paused the birth of a Mac Tower. So it's reason to exist is now gone. It was a political design to appease.
It was 'just' a spray paint pro with better cooling for those higher core Xeons and Vega hot gpus. (Bit heat sink on those high core count Intels???) It was the path of least resistance.
Now? Put a bullet in the iMac Pro's head and drop the entry price of the Mac Pro to £2500-£3500 to include i9/10 m/boards and a 5700XT.
The iMac Pro gets 'cut in half.' So we get the iMac pro with bezel trim for £1700-£3k. Double ram. SSDs as standard. Decent dGPUs. Bezel trim. 32 inch screen.
Apple may have the resources. But the difference between the Steve Jobs Blue and White G3 Tower or Bondi iMac days and Tim Cook's supply chain marketing Apple are fundamentally different.
In soul. Hunger. Innovation. Prioritising the product for the customer. That's how you get the iMac Pro whithering on the vine whilst better tech' options are available and the iMac 2019 got a half azzed effort.
Politics. So the iMac Pro keeps it's unique selling points (cooling...SSD etc...) and the iMac has better price points. I don't like it out certain features that seem 'no brainers' to us customers get kept back to protect Apple's up sell. It's irritating. And it's not just the iMac / Pro they do it on. Sure, I'm fine with consumer, prosumer and pro. But when that stretches out the value equation that forces you to buy a £1700 iMac before you start getting a decent 'apple' rig....it seems blatant. You have to pay way more even to get a deal. And the desktops are designed that way. Don't get the full graphics. Don't get the full 8 cores on certain products. Can't upgrade your ram or your SSD... We were paying more to get 'the deal' in Job's days. But his pricing was mostly 'Apple fair.' Now you're paying even more to get that elusive Apple deal. I wouldn't describe the current desktop pricing as fair deal at all.
That said, any 'substantial' update to the iMac (as rumours hint at...) will swing things back in favour of the customer...provided that new (!) iMac doesn't double it's price...increase by a quarter...or have a £6k entry price.
Apple's perennial problem is 'follow through.' It always has been. And they don't have Steve Jobs driving Apple forward now.
Though I'd say Cook was an adequate steward.
Azrael.