Vircadia's web functionality technically works, and I think it's an okay effort for the tiny team that remains, but it's really at the proof of concept stage. It's slow, misses a whole lot of functionality including very basic things, and has extremely obvious bugs like falling through the floor and the camera getting stuck easily.
So far our take is that it's too broken to just merge as-is, somebody would need to have at least some interest in fixing it up a bit. And for the time being there isn't, and on Vircadia's side the development of it slowed down dramatically.
It's not impossible in the future, but so far things just don't line up right. And it'd be a huge project. The web client is its own thing written from scratch, it'd be an enormous amount of work to make it half as functional as the desktop one.