Only if the publisher of the game chooses to enable it for their title. Why would anyone do this unless they were getting compensation from Facebook to do so
The developers of Apex Construct (note: not Apex Legends
) just announced on Reddit that they are enabling cross-buy. They did of their own accord, because that's how they want to treat their customers. I'm sure other developers will decide to do the same. It also means their game has more chance of being demoed to new users, thus more sales.
This sort of thing makes a Quest a no-brainer for me. I can bring a substantial portion of my Rift library across to Quest on day one.
I think Oculus regards this as a sound marketing move, as it'll get more Rift owners buying the device and buying games that work on both platforms, and helps users show off a wide variety of content to their friends. Another thing is they're enabling cross-play too, so MP games will be far more populated from day one.
Also, with the Valve Index using Knuckles controllers, there'll be far more control parity between Oculus VR and Steam VR. So ReVive will work better as the controls will be almost identical to Rift.
This also works for future Steam VR games that use Knuckles, converting to Rift will be easy as the controls are not hugely different, unlike the vive wands vs touch.