I personally think that it was Twitter Spaces that killed Clubhouse. Clubhouse was pretty novel when it came out, but it had the major downside that your network wasn't there like it was on Twitter and you needed an invite. It was the cool thing when it was the only game in town but once Twitter Spaces came out people realized that you could do the exact same thing over there without needing an invite and you had your entire network there.

It's the same thing that happened to Snapchat when IG Stories came out. Except in the case of Clubhouse it happened even quicker because their was no technical moat.