That's the joke. We had a supersonic airliner, just like we have some cars driving around without steering wheels. But in 30 years the technology never got good enough to become mainstream.

The Concorde wasn't a case of us not being able to build it, though. It was a case of it just not being worth it to operate. Concorde technology was generally fine (27 years in operation). But supersonic transport is a niche even for wealthy people.