Unlikely? Yes. Unheard of? No. It's important to me.
You can plug in at least two more external monitors to an iMac (I am doing it right now). So if my primary display dies, I still have access to the other displays to tide me over until I could schedule having the main display replaced.
Apple needs to offer something that competes in price with a similarly configured Hackintosh.
Why? They haven't done so since 2013 and it hasn't crippled the Mac Group. They in fact are selling more machines than ever - they just are predominately portables now.
Their older Intel Mac Pros were somewhat price competitive with similar spec PC's. This new base model 2019 Mac Pro is definitely not.
The difference is that during 2008-2012, all PCs, be they running Windows, macOS (OS X) or Linux, were constrained by the same bits. So they all had one or two low-core Xeon CPUs, the same general amount of RAM, the same four HDD and two optical bays and the same general number of PCI slots.
In 2019, low-core dual CPUs have mostly given way to high-core single CPU solutions. So PC Workstation makers have now bifurcated their lines with single-CPUs (Z4/Z6 to use HP as an example) and dual-CPUs (Z8). But those PC makers have also adjusted the expandability of their lines to reflect that.
You cannot put 1.5TB of RAM into a Z4 or Z6. To do that, you need a Z8. You can't have a 1.4kw PSU in a Z4/Z6 - only the Z8 can do that. And a baseline Z8 costs a heck of a lot more than a baseline Z4 or Z6 because of that expandability.
The Mac Pro is Apple's Z8 in that it is Apple's most-powerful workstation-class machine. So it's hella expensive because of that expandability - just like a baseline Z8 is. (And yes,
Aidenshaw, I know the Z8 can be configured far beyond what a Mac Pro can be, which is why I am only comparing the two as the top models of their respective lines, not as peers in the marketplace).
Apple doesn't offer the family equivalent of the Z4 or Z6 and it's clear people want that / expected that. But Apple doesn't appear to feel that such a family is worth the investment to bring it to market at this time (nor for the past decade).
And: what about dust filters? As far as I can tell, this new 2019 Mac Pro has none.
No Mac Pro (or Power Mac) model came with them as OEM equipment. I am sure enterprising end users will come up with a solution.
And the Mac Pro's 2x 10 Gb ethernet ports: are those actually incorporated into the power supply?
Based on the location of the motherboard in relation to the ports, no. The power supply would be adjacent to them.
I do think it’s highly likely that Apple wanted to bring out a headless iMac Pro equivalent in an non-expandable Mini or nMP form factor for software developer use cases. They just knew that until they brought out a fully expandable MP with slots, that anything less they brought out would be flamed. So, I wouldn’t be surprised if we see a new beefier Mini Pro or the like with a discrete GPU to handle 6K/8K displays as they become more available.
I honestly think that Apple's metrics show that the majority of iOS development is done on MacBook Pros, which is why they are (finally) consistently updating the model with CPUs with more and more cores. The iMac Pro also seems to be popular with iOS developers based on the developer podcasts I listen to and posts by iOS developers in this forum and others.
And for "headless" development, there is the Mac Mini. It's on 6-core 8th generation Coffee Lake CPUs now, but Intel has 8-core 9th generation Coffee Lake CPUs that would work so I expect we will see an update down the road based on how often they are updating the MacBook Pro. And you can connect significantly powerful eGPUs to the Mac Mini if you need that.
True, if your workload benefits from "all the cores you can throw at it", the Mac Mini and MBP come up short compared to the iMac Pro, much less the Mac Pro. But if your workload is generating revenue for you, then arguably you likely can afford (and justify affording) the high-core Xeon Macs if you desire/are required to stay with macOS.