I own a Vive, but I'm uncomfortable with the idea of paying a company $20/20EUR for what amounts to an emulator frontend - something which would be inherently worthless without the multitude of emulators and the people who contribute to them for free - when the people who make that frontend keep 100% of their revenues to themselves, and do not have any kind of revenue-sharing arrangement with emulator teams.
Quite frankly, the fact that you can download emulators within the emulator itself without agreeing to any possible emulator-specific EULAs or licensing agrements leaves an extremely bad taste in my mouth, especially when considering the fact that many emulators have inherent restrictions on being integrated into commercial products due to using GPL code. The NRA:N team have attempted an end run around the legalities surrounding this, by simply having the NRA:N download the relevant RetroArch cores at run time. It's technically legal in the same sense that in the USA, running up to someone in the street and shouting loudly in their face about how they're going to die is technically legal: it's legal, but it's still fucking obnoxious and you'd be a shitty person for doing so.
The fact is, there have been free 3D arcade frontends before, and there undoubtedly will be again. There's nothing stopping someone from writing a AAA-quality engine to interface with bgfx, other than time, so progress will eventually march forward.