"That leaves Branson with only one option: To try
and purchase a couple of Soviet-era SST's. The Tu-144.
There are at least four Tu-144's in mothballs. "

I think that if the Tu-144 doesn't require much money to make
them legal to fly, then Tu-144 might be an option.
If the Tu-144 doesn't lower this threshold cost to get them flight certified, then the Tu-144 would be fairly worthless for purposes of flying passengers.

Whether it's super sonic, prop plane, or spaceship, the problem is
not the technology or the funding needed to make it, the problem is
getting permission from the govt to fly with passengers- or fly at all.

All the problems of this world can be summed up as some form of a political problem. All political problems are "all about" the way
people "view" reality. The idea that it should be "illegal" for me to put a bullet into my skull, jump off a cliff, or anything else considered irrational to other people is simply "wrong". It may be that's it's immoral to commit suicide, or immoral for someone to persuade another to commit suicide, or for a society to persuade individuals to commit suicide, but passing laws to enforce morality is at best "problematical" and at worse a means of oppression/enslavement.
One way to look at this is by examining what is "adult" in comparison to what is a "child". And the idea that law makers are more adult than the citizens is demonstratively wrong, if anything, the law makers should be considered the children and the citizen as the only responsible sober adult. [not to go careening off, but with term limits- the politicans will be "pre-teens":]
[Btw: generally, I favor term limits- and not because I want babies running govt, but rather, I don't want babies "raised" in alienated "environment" running govt.]