RE Bullet Trains: Japan Vs America
There are 2 huge reasons you see bullet trains in Japan and not in the USA (Ditto Europe BTW)

1)Distance (yes - the pun was intended) - The longest Bullet train route is 593 KM, or 368 miles - most are in the 250KM range, or about 175 Miles. Now lets look at just ONE common flying pair in the US - NYC to Chicago - that's 800 air miles, and around 900 track miles due to the fact you can't really go straight - Twice the distance of the LONGEST bullet train route

2)Passenger density. Now, on Honshu, where the Bullet train runs, there is enough passenger load to justify the fixed infrastructure of trains - picture NYC to Chicago - there is an a LOT of open land between where you are only going to pick up a couple of passengers if you stop

About the ONLY place in the US where high speed rail makes sence is in the Northeast Corridor, and guess what? It has the Acella, and before that, the Metroliner. Yep, the Metroliner pokes along at a mere 120 MPH (Acella is slightly faster). North of NYC, in the Boston segment, there ARE problems, but we have just invested in electrifing the rest of the route (Used to switch at New Haven). The big problem there is that the route is VERY twisty due to the fact that you are cutting across river valleys the whole way

Basically, it comes down to economics. It costs a fixed amount per mile to maintain RR tracks. If you double the miles, you double the cost to maintain that track. You now have to carry double the passengers to make up the difference. if most of the land you are crossing doesn't have enough passengers to pay - it just doesn't make sense