Do you guys think an MMO like RuneScape can be made using firebase?

I was scrolling YouTube after binging game dev videos and came across the spacetimedb video. In it they rated firebase as being useless for online multiplayer and MMOs. But surely that would depend on the genre and game mechanics right? An MMO with realtime combat probably can't use firebase even if they wanted to. But something with less critical timing could probably work on firebase. It seemed like they put firebase down in the video but in my limited experience it seems doable.

Although admittedly the pricing would probably be prohibitive on its own.