You don’t ship something like an XDR content creation display on DSC.
Why not? Visually lossless is visually lossless. The XDR is for content creators, not Hi Fi freaks who deny the results of A/B tests.
You’re missing my point. My point is that DP 1.4 means you could offer more models like the iiyama
Who would offer these?
There are already shedloads of gaming PCs and workstations out there with dGPUs that have regular DisplayPort 1.4 outputs which could run such displays - but you can still count the available 5k 27" displays on the fingers of a boxing glove. That rather suggests that hardly anybody wants the things outside of the Mac world - and its not hard to see why: 5k is a lot of expense, extra complexity and higher GPU load (that could go towards higher frame rates etc.) for a modest quality increase. The idea that 5k is the sweet spot for a 27" display is strictly a Mac thing - caused by the lack of a fully scalable UI in MacOS.
...then bear in mind that the MBA, 13" MBP and Mini (without eGPU) still don't support DP1.4, nor does any 15" MBP or iMac pre-2018. So a big chunk of the Mac market (aka the only people who care about 5k) are going to need either TB3 or a dual DP1.2 cable solution.
which are eGPU friendly for folks on hardware like the Mac Mini. Instead of forcing Specific eGPUs like the Blackmagic be used to hook up a 5K display.
How is that relevant to whether or not a USB-C dock supports DP1.4? If you've got an eGPU with a half-decent modern card in it, you've got DP1.4 and something like the illama should just work, and plenty of eGPU enclosures have USB/Ethernet/laptop charging etc. You're just back to the original problem that there aren't a lot of DP1.4 displays out there right now.