Freight train business isn’t even remotely like the passenger biz.
CSX/NS/BSNF/etc run trains over 100 cars long to a few customers located near existing tracks. A cross-country or cross-state distance is no issue for these companies or the companies they serve.
AMTRAK can only run on the tracks where they are, use trains that are only a few cars long, and carry people who often want to go to places not anywhere near tracks. Thus the pool of possible riders is substantially limited.
Outside of the NE Corridor, most trackbeds are owned by the freight-rail companies. As a result, AMTRAK often has to yield to the trains carrying freight.
Putting in new high speed rail is therefore prohibitively costly because (a) right-of-way must be purchases; (b) rail and fencing installed from the ground up; (c) and now you face the same problems as with passenger rail today: people not living close to tracks and not close to tracks where they work. It’s a cost AND convenience problem, which is why high-speed rail will always fail between bigger cities.
(Note: it works in Europe because their rail infrastructure was there 100 years ago, and the culture is substantially different as a result).