I agree. The New Mac Pro is being advertised to edit 4K and run 4K displays. Apple will want to sell those displays along with the new Mac Pro.
I disagree. They specifically referred to "
third party 4k displays" in the keynote, and I'm sure every word in that presentation was there for a reason.
I'm sure Apple sell far more Thunderbolt displays to MacBook owners than to MacPro users - nice as the TBD is, it is really a high-end consumer display who's Unique Selling Point is as a laptop dock (hence the built-in magsafe). Personally, I'm ambivalent about glossy via. matt, but there are plenty of self-declared pros on this forum who would rather gouge out their eyes than use a glossy display.
Also, if you look at Intel's timeline, TB2 chips are going to be highly constrained until next year. Apple may get enough controllers to launch the MacPros, but both a 4k TB display and any computer driving it would need a Thunderbolt 2 peripheral chip to work.
I wouldn't expect to see a 4k TBD
at least until the MacBook Pros have TB2 controllers (probably not until the next-but-one revision) and 4k-capable GPUs.
Finally, while the current batch of 31.5" 3840x2160 displays are clearly a must for graphics/video pros rendering 4k content, how would they actually work out as a general use monitor c.f. the current 2560x1440 27"? An ideal TBD replacement would be 5120x2880 to give the same icon & default font sizes with 2x resolution. "Screen real estate" is a slippery concept that depends on what content you are using and whether it is freely zoomable (not to mention your eyesight) - but in some cases a 4K display in HiDpi mode might give you less 'real estate' than the current TBD. Or maybe it would work in "scaled" mode rather than HiDPI mode without any problems.