That makes sense. Just out of curiosity, to my point above, how much cooperation from the manufacturer of different systems (Hololens/Xbox/Playstation) do you need to be able to target builds for them?

From experience (old gen and next gen consoles) there is 0 cooperation from manufacturer that you really need, other than available SDK and docs. Yes there are bugs in compilers and the consoles themselves (firmware, HW) but you can usually work around them.

Interesting, thanks for the insight.

On the other hand, adoption is usually easier in niche markets.

Indeed, you might have a point. VR seems to be extremely popular amongst developers at the moment, and they are users of game engines.