Affordable is relative. International business class from NYC to London is probably going to run you $3-4K RT for a business class seat which is absolutely routine for senior business people. Assuming you consider that affordable--which it certainly is compared to a private plane--a 50% premium over that would still seem to be in the affordable category. Doesn't mean it's cheap of course.

The Concorde was a premium over sub-sonic first class but it wasn't anything like double.