I would be interested in knowing what's involved in porting a game from Go or Rift, to Quest, take for example, Along Together, this is a very popular game on both Go and Rift, I have it on Gear VR, but can't play it as I no longer have a Samsung phone, surely with the popularity of the Quest, this would be a no brainer, but as yet, no sign of it, same with Plex, they say "no plans to release a Quest version" why? I would gladly pay for this, and from what I've read, so would a lot of other users.
One big issue is that the Quest store is far harder to get on to than the Rift and Go stores. Oculus are more likely to reject games. I've heard developers say their PSVR accepted games were rejected by Oculus for Quest release.
Technically, getting a Go game to just run on the Quest requires very little effort. It's got the same CPU/GPU family (but faster), same operating system (but newer), same development environment. My students make games for the Go, and I can just sideload the same APK to my Quest and it runs.
However from a quality point of view that isn't ideal. The games don't understand 6DOF, while the Oculus SDK camera controller does. For example we had a game where the player is standing on a rock in a lava pool, while enemies throw rocks at you that you have to deflect with a sword or shield. When I played it on the Quest, I just physically walked 10m away and the enemies were throwing rocks at the wrong location, the game didn't expect the Unity camera to change position.
Same for controllers. A Go game might be hard coded to one controller with a touch pad (those work differently to thumbsticks) and won't understand 6DOF movement. So it might work, but the experience won't be great.
Getting a Rift game onto a Quest is hard, since the Quest is vastly underpowered compared to a PC, so it can require a lot of asset reduction, shader rewriting, optimisation, profiling, etc.
If the Go game is free or from a non-Oculus source (bought it on Itch.io or somewhere), you can probably run it on the Quest just by uploading the APK manually (if you have developer tools) or side loading with SideQuest.