AmTrak is designed to suck. Freight lines own most of the rails, and while they are required to give priority to passenger trains, they avoid this in several ways. Like having the freight trains too long to fit on side rails so the passenger trains are required to stop instead to make way.

Flying is way cheaper in Europe. Partially because trains are taxed much higher than flying.

Not always. Flying from Amsterdam to London is cheaper and faster than taking the train. The train is usually sold out because people still prefer it, but...