Sure, but you have to order it specially (probably ruling out any discounts) and can’t change your mind later (on a device that ought to be good for 5-10 years and several computer upgrades).The VESA variant doesn't cost extra.
well, it is on Apple in as much as they didn’t give MacOS a fully resizable UI (unlike Windows) just two “fixed resolution” UI sizes for 110 and 220ppi. Anything else needs non-integer scaling which puts extra load on the GPU and can create blurring and artefacts (although I think that problem is somewhat exaggerated - 4K with scaling works perfectly well for most purposes).That isn't on Apple, except for the fact that they've priced it absurdly.
4k@27” is “retina“ (1 arc minute per pixel) at normal desktop viewing distances and Windows (and many Linux distros) are quite happy with that - 5k@27 may be better but is deeply into diminishing returns for a significant increase in bandwidth and cost - it is not going to take off in the PC world.