I feel like that's still the point irrespective of Dijkstra's apparent view on the parable. Creating exceptional cases is the best way to increase costs.

Yea, that's where I thought it was going too. I've been on a lot of project lately that try to pre-optimize instead of building a solution and then determining where the bottlenecks are.

A lot of times when we try to build for speed, the real bottlenecks are no where we think they'd logically be.

There's politics involved as well. The solution creates units that all have toilets without countermanding the commercial directors initial edict. Programmers sometimes have to triangulate too.

With the end solution, a passenger is only one car length from a toilet (which would be the case if toilets are at the end of cars for structural reasons anyway) and they only pay for toilets in half of the cars.

I think he understates the cost of putting a toilet in a car, as it takes up space that could accommodate fare-paying passengers.