I guess one question is whether, if we could wave a magic wand and make all Amtrak routes HSR, would it be more or less attractive to travel that way? I suspect for some--those enjoying the scenery, the ability to unplug for a couple of days--the answer would be, it would be worse. For those who can't or won't fly, or have limited vacation time, or are traveling from areas where air travel is unavailable or prohibitively expensive, the answer would be, faster would be better.
At age 75 I fit several categories, but I've always been a geography fan and trains, or ferries have offered the best look at not only the landscape but also at how people make a living along the way. (Most places when I've flown have been socked in. And the seatbelt light stays lit.)
Some years ago, I was at lunch meeting in a franchise restaurant out by the East Salem Bypass on I-5 and overheard a couple arguing about whether they were in Salem or Albany. That sounded silly, but when I looked around all of the signs were for national chain providers of fuel, food, etc. Next time try the train!
This is something too, travelling too fast doesn't allow time to just stare at something that catches your eye unless it is in the far distance and quite large.
As both posters mention, whether it is scenery or how life is lived along the way it is difficult to fully absorb or even absorb at all with high speed rail. (I'm using a definition of high speed as 150 mph and above BTW).