I've not used Firebase, but seeing as it's not, as far as I can tell, "core" Google (i.e., not related to search or advertising explicitly), I'd be concerned about relying on it in any substantial, business-critical, way.
I’m not a VP and there is no way to promise that we’ll “never” be shut down, but Firebase is a successful product and additionally drives a lot of Cloud usage (which is certainly “core”!). I just don’t see any reason why a VP would need to sunset firebase to balance any books.
I've not used Firebase, but seeing as it's not, as far as I can tell, "core" Google (i.e., not related to search or advertising explicitly), I'd be concerned about relying on it in any substantial, business-critical, way.