I remember these worries about Tether not being backed by real cash being a major concern all the way back in 2018(?), if I remember correctly the worry was exactly the same that Tether might not be backed by enough real $ and collapsing when people find this out. Now 3 or so years later we know this is a fact, yet there has been no prophesied collapse in Bitcoin value as a result. (It has lost value lately but to my knowledge for unrelated reasons)
So what is going on here? Is Tether not being backed by real $ not actually as big a deal? Or is the Bitcoin bubble so strong people still buy into it even when Tether is basically a scam?