I could see a high speed line between Dallas and Houston being a good idea.
To be fair, Amtrak has a few lines in the Northeast that are actually preferrable to flying. But cross country, it just isn’t there. You can’t beat physics. A commercial airliner at cruise speed is 2.5x the speed of a “high speed train”.
I fly a lot for business reasons. Most of the people on this forum who bitch about how horrible flying is just plain don’t know what they’re talking about.