That's basically correct. Passenger rail was a highly regulated industry, and it was always more profitable to transport freight over the same lines. Eventually, the private passenger rail companies were basically all losing money, and filed for permission to discontinue passenger service (in the previous regulatory framework, companies needed government permission to make any changes to service), so that Congress basically created Amtrak to take over the prior passenger lines. As it stands, though, Amtrak needs to lease/license access to tracks it doesn't own, so it's hard to increase speeds or service, as the track owners would need to give permission for the upgrades to the track or the effect on timetables. That's even true of the Northeast Corridor, where Amtrak owns most of the track, but some segments are owned by freight rail companiex CSX and Norfolk Southern.