Yeah, and dont forget the scale.

Japan is building a maglev line right now. But they have >60 years of experience with high speed rail and the whole concept is established. Even then its "only" about to be 400km to connect three major metropolian areas. https://en.wikipedia.org/wiki/Ch%C5%AB%C5%8D_Shinkansen Still:

Construction is expected to cost over ¥9 trillion Japanese yen (approximately $82 billion USD) and commenced in 2014. The start date of commercial service is unknown,[...]The Nagoya–Osaka section was planned to be completed as late as 2045, but the date was moved to as early as 2037 following a loan from the Japanese government.

Chicago to New York are more like 1200km and major stops between them are like Cleveland and Toledo. Uuuh... just build regular ass rail with a bit higher specs for higher speeds...

? ICE 3 trains are already running 300 km/h in Germany and 320 in France. Nothing "ahead of its time"

The main issue is that you need absurd amounts of resources just to build the track alone.