The prolonged period of austerity and under-investment applies equally to Amtrak. So one should expect to need a significant bump in subsidy for any attempts at privatization of Amtrak to succeed. In case of Amtrak it would be ti make up for 45 years of under-investment in Amtrak and before that lord knows how many years of under-investment by the private sector. So the amount as proportion should be significantly larger that what was thrwon at the British Rail system to support privatization. Is that going to happen? Unlikely for both the additional investment and privatization. People are just blowing smoke. The only two choices at present are shut it down or continue with the current setup substantially.
In the USA, the tracks are largely owned by freight companies that are on the whole profitable.
In the UK freight is not as lucrative as in the US. For many years under BR, freight required a subsidy and despite severe pruning of the freight network (there are very many lines in the UK that have passenger trains but no freight at all today) and multiple reorganisations and price hikes, this didn't seem to improve. Many people predicted that freight by rail was in terminal decline and would sooner or later terminate altogether. Money was pretty much being haemmoraged no matter where you looked. In the run-up to privatisation the freight business was split into into several sectors which were sold off individually. The fast intermodal business serving the major seaports was bought out by a management consortium and formed Freightliner. It is doing quite well today (and has been sold on several times), but to be totally honest it has received quite a bit of government support in the form of improvements to terminals. The other freight sectors were all taken over by EWS, a company owned at that time by Wisconsin Central but since taken over by DB and rebranded as DB Schenker. They brought in some innovative practices and invested heavily in new equiupment and actually managed to grow back some of the traffic lost in previous years. However rail freight in the Uk is not inherently profitable as you just don't get the same sort of distances as in the US. Furthermore, the newtork is largely built up for passenger trains and freights often have to weave in and out as capacity allows which does not allow for competitive scheduling.
Since then some third party freight operators have also started running, often by cherry picking the most lucrative contracts without providing a coherent system. Freight growth has also been helped somewhat by the worsening of road congestion due to fewer funds being provided for highway building compared to the past, meaning that delivery times by road and also the reliability of road haulage has taken a hit giving the railroads some upthrust. For example a lot of supermarket supplies go by rail these days, as supermarkets cannot afford emtpy shelves and are prepared to pay the extra cost. This sector that was virtually non existent under BR and supermarked managers at the time evn laughed at the concept of putting stuff on a train. Even the major road transporation company, Eddie Stobart, is sending stuff by train these days.
But even so, all this is growth on the back of the passenger system and using infrastructure built for passengers. If these companies had to own and maintain the tracks by themselves, they probably couldn't survive. So maybe on paper the freight sector is paying its way while passenger trains are living off tax money, but in reality that is something of a distortion. There probably wouldn't be much of a rail system in the Uk at all without the government putting money in.
So what i wanted to say was that this isn't really the same as Amtrak. Amtrak uses freight railroad tracks and can continue to do so. Maybe the government would need to shell out money to raise the speed a bit here and add a station track there but that's no way the same order of magnituide as jumping in and taking over the entire system.