For the government train people (those in favor of the BR to NO boondoggle)

Why hasn't Private done it yet then, IB?

Because the government granted a monopoly on all passenger rail to one company and regional monopolies for the tracks themselves to a small handful of corrupt entities (most owned by Warren Buffet), AND gave the line owners right of way over the passenger trains.

Basically, the government monopolies give zero incentive for private entities to develop new infrastructure, and regulations likely would make that a non-starter anyways.