I think just like all things on the world wide web, a majority of it will be implemented sub-par, perhaps even terribly. It's not so much WebGL that is the bot

I think just like all things on the world wide web, a majority of it will be implemented sub-par, perhaps even terribly. It's not so much WebGL that is the bottleneck as all the experimental implementations of it (guilty as charged here). Those people like Mr Simon here who take the time optimize every last bit can indeed make it purr. Everything on the web starts as a framework or some proprietary bundle of some kind, and if it proves it's merit, it may just get built into the W3C standards themselves. We currently have a low level tech (webGL) in W3C, and libraries like three.js are providing the get-you-by to elevate it to average code legibility, but I think we are still a long way off from having 3D be a javascript-native ability for the average developer in a peformant implementation, at which point we could really expect this www-metaverse experience getting hyped every which where to blow the lid on this two dimensional web we're currently stuck in.