>And what could or would Sir Branson do differently from what AF and BA have done for the past 27 years? <
It's called Marketing! You can have an "inferior" product but if you get your marketing right you are in business, at least for a while.
Look at the top of many successful enterprises and you will see an entrepreneur. Whether you love him or you hate him that is what Branson is. He wins some and he loses some but, on balance, he seems to win more than he loses.
If Branson thinks he can operate Concorde profitably then I say let's let him get on with it.