"Concorde was untenable to most mere mortals who could only dream of flying in her."
All you needed was lots of money.
So far as flight crew were concerned, the Concorde fleet was listed on the annual bid-list, but very few (IMO) pilots bid for the type because...
1. It was a 7 year freeze for an F/O.
2. It was a 'final type' for a captain - ie. you're on it for life.
3. The route network was remarkably limited.
4. There was very little 'hands-on' flying.
5. Every sector was (as a flight-engineer pal of mine said of his Concorde job) "like a flaming sim-check", with so many things going wrong!
6. Fuel was always a real worry. Remember the Flight Manager who flamed-out exiting the runway?
It was a wonderful icon, and I suspect that most of us would have killed to fly it ONCE.
But as a full-time job - no way.