For Google, it makes sense for them to request at least some "standard" methods. If the number of DID methods is sufficiently large, Google won't be able to use their network effect to dominate any of them. Surprise, that's the aim of the spec.
For Mozilla, it makes sense to support a small set of DIDs, their resources are not infinite.
As a user, I want to use the DID method that works for ME. For example, https://en.wikipedia.org/wiki/BankID is used universally in Scandinavia and I would not see why would anyone use DID for identifiers of "real world" things if a govenrment-accepted mechanism cannot be used (eg "did:bankid:*") for signing those identifiers etc. Because I already use BankID for all important authn things in my daily life. In Estonia, ID cards are used for legally binding signatures since forever, I can totally see how they might want to use that to sign their DIDs: https://en.wikipedia.org/wiki/Digital_signature_in_Estonia
Regarding Web 3.0 garbage in the registry: just ignore it, nobody is going to use it seriously. Those entries are just marketing by those projects. If it was up to me, I would split the registry into two sections: registries with significant stakeholder backing (BankID and the likes) and everyone else (so that you can ignore them).