The only area where a bullet train makes any bit of sense in this country is the Northeast Corridor.
There are other potential corridors. Tampa-Orlando-Miami might work. Chicago - New York if you could take it down to 4 hours (from the current 18.5 hours) would compete with air. San Diego to LA in under an hour would draw passengers (folks are already willing to take the existing rail service over driving). LA - Vegas might work.
What would probably sell better than bullet trains are auto train services.
What about the Texas Triangle? Your name indicates you know Texas.
The terrain is probably favorable. (I’m one of those easterners that thinks Texas is flat)