If you are looking high end cases they are out there, just hidden.

Such as,

Dune Pro: https://www.dunecase.com/ InWin lines: https://www.in-win.com/en/gaming-chassis/z-tower/ Lian Li, Cases that are desks, and other high end designs: http://www.lian-li.com/

If you have money, you will find people looking to sell you high end cases.

I personally use Fractal Design cases, they look good, made of thick steel, and are cheap enough I can replace them more often without feeling bad.

+1 for Lian Li. They're an excellent case for building in. Good fan mounts, water cooling mounts, thick steel, good layout for PSU / HDD placement.

I have several Lian Li cases as well. Most (if not all?) of their cases are aluminum.

I’ve got a Liam Li PC-011 and it’s steel. I had to drill holes for my custom reservoir, that one at least is steal

I had a LianLi, and it was the best case I've ever had.

I found that putting the large case (standard μATX, for low noise) on a stand under the desk (carpet+dust considerations) with a small homemade wooden box for IO on top of the desk worked well. No reason to have the big box visible when you only interact with a percentage of it. Just like a power distribution board is in its own closet and you interact with it using power outlets, the desktop computer was away and I interacted with it using USB devices and the on button. The only reason to get near it is for maintenance.

The on button is just two copper wires that need to make contact in order to boot the computer. You can use any old button from a store or make one yourself, or use a wireless one if your computer is really far away. The USB hub's case can be removed, and if you use the motherboard's internal audio chip you can find ready to use AUX extending cables for nothing.

Of course if you don't want to make a custom IO box you can just use a regular USB hub and a remote.

Are you including the cost of the 27" 5k screen when comparing the value of the iMac Pro?

Or the ECC RAM? Or the insane I/O with four thunderbolt 3 ports?

I find that people often don't compare Macs spec for spec. They just pick and choose the specs that they care about which isn't a great comparison. However this also speaks to the freedom of PC building - you can pay for only what you need.

A Ryzen CPU will expose 20 PCI-e 4.0 lanes to external devices. That's almost 3x as much I/O as 3 Thunderbolt 3 ports. A Threadripper will expose up to 72! Sounds like a downgrade to user-selectable I/O to me, not really a selling point.

>I find that people often don't compare Macs spec for spec

I find people often hold one thing from the iMac that's not really relevant as justifying a whole laundry list of failings.

I'm including my screen in the price of my build, I have ECC ram and two GPUs and I'm still a fraction of the base model price and outperforming it.

Gamers Nexus has a lot of reviews for cases of all sizes, it's how I ended up with mine: https://www.gamersnexus.net/reviews/hwreviews

Check out the Meshify C, it’s basically yours but with a really cool design on the front panel. Other than that though, I agree with you that there isn’t much on the market that stands out in mATX and bigger. The Thelio seems like a great design but it’s not available as an empty case.