That's the point.

One penny pinching solution, improperly evaluated, pissed off customers, made the company less efficient (man hours working on a previously smooth process), and resulted in a direct capital expense.

All in all, they probably took a loss.

No, it would have cost the same. That was, to me, the point of the parable. The initial cost savings was absorbed by the cost of purchasing the additional cars necessary to implement the N/2 fix.

Same problem as with airlines-- a toilet would probably remove 4-6 paying passenger seats, which means less money. Toilets don't generate revenue whereas seats keep paying for themselves many times over.

I think there is more to train toilets than that. You need somewhere for the wast to go, and waste disposal, cleaning, maintenance, stocking all have to be done on a regular basis.

It's a parable, not a real world situation. It's meant to illustrate how an appropriate abstraction can remove complexity from a problem as requirement get piled on.