Time is a resource that once spent can’t be gotten back. I agree that time spent inefficiently is another huge factor, but I don’t think that’s going to be seen as a strong argument in this community so I intentionally omitted it.

I would be careful about making generalizations linking mental illness and public transport. I know you’re commenting based on your own experiences(which are valid), but it’s not going to be the case everywhere and will vary depending on the city support systems, which to your credit you did touch on. Any sufficiently large gathering place, regardless of purpose, is going to have its fair share of weirdos in the end.