And frankly, Mouse is the only one who cares about the gauge other than historians and those who have to write specs for equipment. Otherwise, it is a transit system. People ride it. They hope they can find a usable seat or room to stand. They (usually) get where they're going in one piece with all the items they started with. That's what matters at this point in time.

You've heard the term "sunk cost?"

And rejoice, they could have chosen Brunel gauge (7') for stability at 80mph in hurricane-force crosswinds.