Anyone is entitled to an opinion. Just don't try to pass it off as fact if you cannot back it up.
Twotun is a current Concorde Flight Eng and I am a current Conc. pilot. Please allow for that in our posts - I am afraid that our opinions are somewhat clouded by fact.
The requirement for three aircraft is easy to explain, one in LHR, one in JFK and one spare to cover planned line maintenance. Count them - it comes to three.
As it happens, given the initial revised schedule for the BAW002 it would, in fact, be possible to to operate a daily service with two a/c, but only until the first B check.
As for your tendentious quoting of the horror comic, I would be fascinated to see some statistical back up, since I can personally vouch for more engine failures/shutdowns, hydraulic, electrics, etc probs on EACH of my three previous 'blunt' types. Guess I'm just lucky??????
I do concede that the SSC generates a higher proportion of ASRs relating to RTOs than other types, but these are generally reheat related and are, in safety terms, a non-event owing to the low speeds pertaining.
Sorry if I've spoiled a good argument with facts.