Saw this yesterday, amazing if it happens.
This one of the handful of aircraft that people with no real interest in aviation recognise and will stop and look at and or watch.
Yes, it certainly would be popular;r - & as someone who was planning a cruise/Concorde return flight, I would buy a ticket! 
However, the important item not mentioned is engineering. Who will be the engineering support company/companies? Aerospatiale, the joint venture that designed & manufactured the type, is now BAE Systems and EADS Airbus. Will they give design authority? Provision of spares? We have seen the comparable difficulties with the Vulcan - & that is a display aircraft rather than a pax carrying one.
Concorde also has much more complex systems than the Vulcan, such as a tripped hydraulic system - although I note that the one in Manchester (B-BOAC) had partial systems powered up some while ago - but this opportunity got “killed” - think that they can do something similar with the one at Paris Le Bourget museum? The one at Goodwood (G-BBDG) ain’t going anywhere, it was cut up into sections for transportation.
The BA example at Heathrow, G-BOAB, is probably not in the best state - & some of the flt deck instrumentation is now fitted in G-BBDG (along with a lot of cabin interior items).
G-BOAF - at Bristol Filton - seems to be in good nick.
The reason BA stopped flying it was the withdrawal of design authority; if they couldn’t afford it a decade ago, then a bunch of amateurs, however keen, will never afford it.
Unlike the Vulcan, Concorde had a civil Certificate of Airworthiness and changing to a permit to fly is not an option. They tried that method a decade ago.
One is reminded of the response to a suggestion that the Titanic be raised: “It would be cheaper to drain the Atlantic”
Where there’s a will there’s a way.
Look at the number of steam railways operated by amateurs. I knew a bloke who did this whose background was heavy engineering, he loved it and there were others who all do/did their bit.
It is different for a commercial operation like BA (and Air France) to say it’s not viable, as they were looking at a purely commercial passenger carrying perspective. A lot of the steam railways today were axed as they weren’t commercially viable in the 60s, but today operate appealing to the tourist. The problem with aircraft is the costs, as such it’s success will depend on who gets involved and if they have the influence to attract ‘real money’, rather than lots of ‘little people’ who wouldn’t be able to provide the finance and then how they market it. Frankly if there was enough pressure things could make it happen.
Not quite sure where you are going with this. Are you really comparing putting a supersonic airliner, sorry THE supersonic airliner back in the air with operating a steam locomotive? I have experience of both.
BA really wanted to keep operating “The Rocket”, it was making profits and was an icon, but it was a very, very complex aircraft built out of 1960s technology and no-one was prepared to accept the design authority for it when Aerospatial backed out, nor did any company have staff qualified to do so. An accident that was proved to be a technical issue would bankrupt any company and there was no chance of any income to be made from accepting that responsibility. The aircraft was not the trouble free item that the general public believed it to be with a constant stream of modifications. Did you know that at least twice major items (in one case most of the rudder) came off in flight?
There was a move to operate one on a Permit to Fly when they were retired which was totally rejected by the CAA.
They have all now had over a decade of standing on the ground, usually outside, which will not have made them any better.