I am only speaking from the developer side.
Basically VR is a pain to Dev for and the number of potential sales is low due to limited numbers of consumer units in players hands.
Ideally Devs would like to release VR titles across all 3 platforms, but there is heavy segmentation.
PSVR and Rift offer the same type of gaming experience, but PSVR titles need to have many corners cut which makes them less viable as PC releases (including the Vive). So developing PSVR fist is not ideal.
Vive and Rift offer the best overall experience thanks to poly count, resolution, and responsiveness, but porting down to PSVR is problematic, due to again the power of the PSVR. Multiplatform dev becomes seriously problematic.
And then there is the same old issue of each manufacturer wanting exclusive titles, but its not viable to 3rd party devs. So its up to the manufacturers to produce these, but in turn it creates even more segmentation.
And lets not even start with the Room tracking Vive stuff. Not only is it a pain to dev for, it actually sees very low long term engagement. Its a cute idea, and a nice PR flashcard, but currently its not a viable gaming experience outside of very niche experiences.
Lastly PSVR has created an experience that is less than stellar, and more likely to induce nausea. And all 3 fail to allow games to have decent gaming sessions. Comfort, or simulator sickness issues means you're topped at out 20-30 mins at best for most players.
To succeed on a Development standpoint the units need:
to be much cheaper
To stop pushing exclusive content
Have parity across devices/industry standards
Not cause sickness in users
More market saturation (the audience is EXTREMELY limited even on PS)
Ideally be wireless
So for the time being VR will be dominated by 1st Party games until developing for them is actually profitable for developers.
VR studios are closing because the sector is a mess on the development side. Its not viable to invest in a premium VR game, so we are left with niche and narrow focused experiences.
PSVR has massively increased the market, but its still very small, and also very limited by what can actually be produced by the PSVR. In terms of fidelity, reposivenes, complexiry and control the PSVR loses it wow factor much quicker than the other platforms. The engagement figures (3rd part only) indicate this quite clearly.