I'm not sure I disagree. I don't have numbers but, anecdotally, you sure hear a lot of "But flying is such a hassle" which is sorta true but not sure how much more than it's ever been especially if you're willing to pay a bit more. I'm not sure how many people translate that into "So I'll just drive 1,000 miles instead."
In Europe (and the US Northeast Corridor), I do favor trains to avoid going to and dealing with airports, but they're no panacea either. And I say this as someone with the various passes that make flying easier.
International trains have security too nowadays. In fact they're trying to feel an awful lot like planes...
It is what it is. Governments can't risk the bad publicity of a terrorist attack. A car accident doesn't even make the news.
I can drive for 5 hours, or take the 1 hour flight. The one hour flight has a total time of over 5 hours when you include getting to the airport, clearing security and getting bags at the other end. Plus I will not have a vehicle. For one person the cost is probably a wash, for two or more driving will be cheaper. 1000 miles does tip towards flying. Under 300 miles driving is going to be way less hassle to drive.