Boom is taking the government's role, not BA's. I once did a back of the envelope calculation which suggested the government could have lost less money paying for a NY- Europe business class ticket on a regular aircraft for every person ever to fly Concorde. It was as spectacularly bad commercially as it was impressive technologically.

It was a sustainable business for BA because they got several aircraft at giveaway prices (the minister who sold them conceded it may have been the worst deal ever negotiated by a government!) which they could charge extortionate rates to fly on, but they still weren't flying more than one of them at a time very often.