The thing I find so surprising with such programmes is that they always want to take such a massive leap from Concorde. Yes it was developed during the 1970's but let's remember that the USA never got anywhere near to producing even an equivalent to it.
The leap in technology required to go from M2.0 to M5 is probably beyond that currently available and even if it is available would be so incredibly expensive as to preclude being commercial.
Technology demonstrators would need to be designed developed and tested well before such an aircraft could be produced.
Don't hold your breath....