Valid points but you have to remember that Xeons are expensive and the iMac is a consumer machine. Xeons are meant for reliability not cost/performance. Essentially to implement them the iMac price will soar making it even more niche.
The only product apple has ever cut the price while in production was the Mac Pro and it still isnt enough to get people buying it. Its not in Apples logic to cut prices look at the mac mini... super old exactly the same price.
You have to remember that apple has been trying to kill the pro scene for a long time. The last good update was from 2008 to 2009. Then the 2010 came out and 2 years later the 2012 and was exactly the same machine. Essentially 4 years with no difference to the 2013 mac pro. The 6,1 came around and they tried to reduce the size which im assuming cut production costs, shipping and obviously they were band in Europe for their poor environmental specs. The 6,1 cost more but it was a big big flop. Then 5 years later the iMac Pro because the rest of apples line up is suffering from not having a professional option.
For many pros a macbook pro even in 15" form is a secondary portable machine as they dont come close in sustained performance. The iMacs have never been really powerful desktops just mid range yet still cost up to £4000. If there is no powerhouse which there wasnt for a long time then what do you do? Its just apple rape.
At the end of the day for many including me the iMac Pro is a 2013 mac pro with a screen built in with no option of changing ram or the SSD.... IMO its even worse. The last thing I want is for Apple to replace the dedicated headless mac with a parts bin special iMac pro which wont last as long and they obviously feel no need to support.
In terms of ram, if a chip fails its probable the machine wont boot. With the iMac pro you could have a weeks downtime to get it turned around. Its unacceptable, whereas with a normal machine you pull the stick out keep working, next day a new module and put it in. Job done. Why would you make it more difficult for yourself.
I dont think swapping ram makes you a techie, its the most simple swap on a computer and I dont think people who buy high end machines have no idea how to.
For example my 2010 mac pro was my main machine all the way up to the end of 2016, in that time I had upgraded the CPU, ram, graphics card multiple times, added USB 3, internally it has 22TB of HDDs that means I dont need to have two external raid arrays saving me at least £800. Same with internal graphics options.
It cost me £1899 and probably another £1000 in parts in that 6 years. The drives probably another £500. £3399 in total for a 6 year machine... the value prospect of this machine is off the chart for me. If apple had made another would I have bought another? Most definitely, its apples own fault for not offering another similar machine. They dont need to reinvent the wheel for this sector. Just give people what they want.
The iMac Pro is no more powerful if you compare year vs year if anything the iMac pro is probably slower because tech especially from intel has not improved much at all from 2012 vs 2017. The worst bit they have removed every user serviceable option and if it stopped working because of a stupid issue... I couldn't fix it. Yet its still more expensive and has less functionality.
Thats what pros want, the creative market is a tough one at times and its very competitive. Just having a PCI graphics and HDD options means again the £800 saving on an external raid device and £400 on a graphics card enclosure. £1200 its not small change is it thats a 1/3rd of my total spend on the Mac Pro over a 6 year period. The ability to choose your own monitor too, that 5k is beautiful but even the vega 56 feels sluggish the 64 is the only graphics card that I felt was adequate. Its overkill and gets in the way of productivity and program performance.
Again with features the mac is notorious to get them last because of the volume. Especially the iMac, the volume will be so low compared to the macbook line. No chance the mac will get face ID first although it makes perfect sense. The macbook pro will get it first, because its volume is far higher than any mac desktop.
Apple wont clock the 8770k but what I mean is that its a screamer as it is. Apple must know the issues with the current iMac with how bad the cooling is and really buying anything over the i5 series is a bit of a waste of money as the experience is worse and the added performance lost due to heat and throttling. If they put adequate cooling in the iMac the 8770k would compete very well for 90% of application vs the 8 core Xeon W chip. This would mean a redesign which I cant see happening, regardless that the chassis is the oldest and longest living design in iMac history.
Another issue with the Xeon W is that it basically is the same skylake chip without the extra features which a lot of normal people will benefit from also means a hefty price increase... The only benefit to the Xeon is ECC... but its not necessary and its slower, from my experience it burns itself out with sustained use.
The Xeon is also not interchangeable with normal boards meaning apple needs to design another board if they dont recycle the current one...
Check it out yourself.
At the end of the day with a decent desktop cooling implementation it shouldn't have to use low TDP cpus. The whole situation is BS. Reduced features and far more expensive.
People forget how good value the Mac Pro was and now the standard iMac in similar configs are 2k more and they dont perform as well.