We're still spending a lot of time and money recovering from Conrail's stewardship of the rail network. Lines closed or single-tracked, etc.
Outside of that, there's probably about 100 miles of track that can support 220mph speed limits in current right-of-way (large sections in MA, MD, and RI). Adopting better trainsets (switch to EMUs from locomotive-hauled) and rebuilding track to higher speed limit standards would help there. The track from about Kingston, RI to New Rochelle, NY basically needs dedicated HSR. You can, for the most part, use the existing I-95 ROW for this, and east of New Haven, there's basically no takings you have to consider; west of New Haven, you need to do a lot more takings for curve straightening, and that is going to be an eminent domain disaster.
This is like arguing that the Trans-Siberian Railway is not viable because the distance is just way too large: the Trans-Siberian Railway is not even a high-speed railway.
To travel from NYC to Chicago on Aug. 21st:
Flight: $124 nonstop (2hr 40 min) or $85 with layover (7 hours)
Greyhound (bus): $170 (23.5 hours)
Amtrak: $144 (19.5 hours)
If you value your time and/or your money the flights usually win
Not sure what you mean by this. There is already a passenger route between Chicago and LA. Has been for a long long time. It's called the Southwest Chief it runs from Union Station LA to Union Station Chicago multiple times a day.
Like most airports, you mean?
I'm not against subsidizing train travel, but you should be getting something for it. You could decide to add a train between any two places and dump money into it until it's cheap enough to fill up. The question is if you're causing people to take the train who would have otherwise driven/flown, or if you're just subsidizing a new market.
I don't live in either city, but the concept of taking one of the other long-haul Amtrak lines from Chicago to Seattle has seemed interesting to me. It's not that expensive and it would be quite scenic. That said, if I took it, I'd be flying to Chicago, then taking the train, and then flying back home from Seattle. That's not replacing a flight/drive, it's creating net new flights. Is that the sort of train line that we should be subsiding the existence of? I can see the value of doing it as a matter of culture and history, but if the goal is to reduce the carbon emissions of flying and driving, it may actually be counterproductive.
Maybe they think that trains are like planes, and that you have to stay on them for the entire Chicago-LA trip, rather than getting off (or on) at one of the 50 other stops?
The Amtrak Southwest Chief exists. It may be subsidized by more profitable routes in the northeast, but it is nearly always full.
First, much of the country is never going to be capable of having efficient passenger service. There is no way you can make a viable passenger route between Chicago and LA; the distance is just way too large.
Second, passenger and freight rail just doesn't mix. A lot of European countries look at the US rail market and ask themselves "how can we move that much freight by rail?"
Third, nationalized rail has not worked out well in the US. The article here already talks about Conrail (the nationalized corpse of Penn Central) a little. But Amtrak's stewardship of the Northeast Corridor has been abysmal--here is a linear corridor about 500 miles long connecting 4 of the top 11 largest cities in the US, entirely in public hands, with no freight traffic running along it, and yet we still lack a proper 220mph high speed rail with frequent service along the corridor. US commuter rail systems generally suck even harder than that, and again, they are already all publicly owned anyways (and many of them can't even use the excuse that they rely on track owned by other people).
Finally, if you read the article and particularly some of the comments closely, you'll notice that the problem here can be boiled down in simple terms to "cost minimization in one domain creates secondary consequences that have problems elsewhere"--given the size of the US, even a nationalized system is going to have internal business unit divisions that will keep the same underlying problems. The comments give some examples of such intra-service turf wars causing solutions to not work out.
As an addendum, I assume by "entirely created by the US government," you're referring to the land grants to railroads. Well, land grants to western railroads--the eastern half was built out before they started giving out land grants. And the land grants were only given out during a short ~30 year window. I don't have the exact number on me right now, but I think it was about 40% of the US railroad mileage that was awarded land grants. Hell, one of the transcontinental lines received no land grants whatsoever.