If you could dislodge the rail lobby, why waste time and money building a parallel national rail system when there perfectly serviceable existing tracks that can be converted to be operated for the public good? This is one of the things Eminent Domain would be good for, as opposed to seizing people’s homes and giving them away to property developers.
The pre-existing rails are currently at capacity with freight trains, and for good reason. We can't replace that without harming the logistical system that keeps the central US at something approximating the first world.
It's better just to build more capacity and reserve it for passenger.
HSR for passenger already requires dedicated tracks. Mixing 220mph trains and 75mph trains tends not to work very well. (Not to mention the curvature requirements precluding a lot of existing right of way).
The real problem is the lack of demand for passenger traffic. HSR ridership falls off a cliff around 2-3 hours; in practice, you're limited to looking at city pairs within around 500-700mi max, ideally all in a nice line, and outside the NEC, there's just too few of these pairs.
The pairs are more numerous than you'd think. Put 560 mile circles around Atlanta, New York, Chicago, Dallas, Los Angeles, and Seattle and you basically cover most major metro areas in the US.
A single pair by itself is not enough to make the investment cost worth it. (This is the Midwest conundrum--there's actually a decent selection of third tier cities, but no three of them are close to collinear).
Three of them can be collinear if you consider Chicago a viable third city (e.g. Indianapolis - Milwaukee).
Some city pairs are kind of isolated (St Louis, Kansas City).
Some have decently sized cities that you can connect in a linear fashion (Chicago > Indianapolis > Louisville > Nashville)
And some you can serve in a somewhat roundabout fashion while still being time competitive (Chicago > Indianapolis > Cincinnati > Columbus > Pittsburgh).
I agree in principle, but be careful with throwing around "perfectly serviceable" like it means nothing— the suitability of tracks for running frequent, high quality passenger service rests on a lot of factors: twinned track, electrified track, modern signalling, corner radiuses, etc. Most of this isn't an issue for pure freight and it's expensive to fix/upgrade.
