Clubhouse vs Twitter Spaces?

Clubhouse is suffering from a lack of quality that I think Spaces does not have - Spaces is tied to hard-won and lucrative Twitter followings, whereas Clubhouse is rather divorced. It's like a podcast vs. a radio show. The result on CH is a lack of rigor & excellence, which shows up in the form of endless tabloid-like, sloppy rooms and unqualified pseudo-intellectualism. When CH is good, though, it's very good - just depends on the moderator and skill of the guests.

I don't like that Clubhouse is only available by invitation. Why can't I register at will? Why should I ask someone for invitations?