Doesn't matter whether you're actually going to buy - if you just pick the "most expensive" from a sprawling range like Dell's you're sure to find the worst value-for-money, or something totally non-comparable. You've chosen a system with water cooling and a massive gaming case that is, well, compensating for something...
The "most expensive computer that Apple sells" is a tricked-out iMac Pro that has an extra digit in the price. Its not a way to compare systems.
Admittedly this is a good point, my point of comparison was garbage and I have no problem admitting I was wrong and (therefore I am) dumb.
However if we are going to be fair lets look at Dell's All-in-Ones. I used a Dell All-in-one I could customize which is the Optiplex which is also there "for work" model. This includes a 3 year warranty and onsite service.
The default SSD appears to be a 128gb SATA SSD.
Now this only doesn't mean much without.
Comparing across OS's and file systems isn't exactly fair but right out of the gate it would need to be a class 50 to entertaining the idea of fair comparison.
Meanwhile, if you build a Mac to a ~$2800 price you're quite likely to end up with a 2TB fusion drive with only a 128GB SSD component that isn't easily upgradeable - for a couple of hundred bucks you can easily add a 1TB SSD to that Dell in addition to what is there and you are unlucky you might need to use a screwdriver.
This is where Apples "devil is in the details" approach is lost on many people. MacOS's "Core Storage" operates on a block level when moving data to the SSD. This is levels of data the user can access since we are working at a file level. So not only are portions of programs moved to the SSD but portions of individual files as well. 128gb of SSD with a fusion in practice can operate with the real world "feel" of a MUCH larger SSD since you don't typically use ALL the data of a program and OS. For example if I only use 40% of what FCPX is capable of then that is all that will reside on the SSD. Plus since its operated through the native OS its smarter than all other hybrid solutions with caching, prediction, and background operation. At the speed SSD's apple offers its more of an Intel Optane solution and to be fair that Dell offers that option but you'd need to get a HDD.
I've never used Intel Optane however at 16gb I feel like you are picking your poison really. I would prefer an SSD just to be safe.
In the end for comparison to the mid tier non upgraded 27" iMac for $1999 I came up with this.
Which is a Dell 27" 4k, i5 8th gen processor (8600), 8gb RAM DDR4 , m.2 SATA 128gb SSD, 1tb 7200rpm HDD, nVidia 1050 4gb (only option), HDMI, display port, no TB3 though, IR camera (logging in?), windows pro recovery (FileVault). MacOS comes with an Office suite but I excluded Office 365 ($250) from the optiplex to account for its 3 year warranty although that gives the Dell and advantage since AC+ is $169.
I feel this comparison trades blows with the iMac. And in the end you have a plastic Dell All-in-one that is better at some things and worse at others for <10% less.
Upgrades on the other hand, Dell offers better prices. RAM is really only the direct comparison because the iMac upgrades goto a 9th gen Intel, and PCIe SSDs that are better. But with RAM the upgrade from 8-32gb is $228 dollars more with Apple with what is otherwise identical RAM (DDR4 PC4-21300). Conversely Apple supports unto 64gb and has 4 dimms vs 32gb and 2 dimms with the Optiplex. Plus there are larger SSD options which are difficult to price out at all. I don't think its coincidence Apple (and Dell) don't have direct comparisons in all aspects.
I couldn't find a customizable Inspiron 27" at this time for some reason.
I'd agree with that, but part of the reason is that nobody else is really trying to compete with the high-end 5k iMacs at the moment so there's nothing really like-for-like to compare it with. Still, the main reason the iMac is value for money is that it includes "$1200 worth" of display that is only worth $1200 to you if it was actually what you wanted...
You're speaking of 'value' which is subjective and I completely agree. You could say the same about Apples SSD's, my iMac has a SATA (Samsung EVO) and my MBP is PCIe. Without a specific requirement (4k 10bit video editing for example) they're comparable. I would recommend SATA to an average user purely due to the value perceived by me for their needs.
Value is why we will continue to agree to disagree. I don't expect to change your views and if you don't feel there is value in the iMac that you should definitely get something else because you'll never be happy with something you don't find value in.