> operated profitably

Until the oil shocks, and until “normal” planes became faster.

I happen to know a couple older and very wealthy people, and they say that even though Concorde was a lot of fun when it was a novelty, they now prefer to have a couple more hours flight and enjoy a 777 premium cabin rather than the cramped Concorde interior.

Anyway, the proof is in the pudding: if no one but national carriers ever bought and operated Concorde or Tu-144 at scale, it's not because of some Amish-like sentiment in the flight industry, but simply because that didn't make sense money-wise.