The same thing holds in transit. "Quality" transit isn't the fastest or the most comfortable, though fast and comfy are nice to have. "Quality" means there's plenty of it, so you can get where you want to go when you want to go. That means frequency. For instance, what carries more people: 10-car BART trains every 20 minutes, or 5-car subway trains every 5? Even accounting for the smaller cars on the subway in NY or the L in Chicago, the answer should be obvious. The other point is that, for transit, you need a published schedule if headways are more than 10 minutes; less than that, and the wait is short enough on average that people can just head over without thinking about when the train or bus will come.

Of course, having high-frequency train service on something like Amtrak means running with some empty seats. Either that, or a lot of standing room. Airline execs don't like that - it's not "making money" unless it's full. Unless you're Southwest, which likes to be full (have you ever been on one that's not?) but will accept an occasional empty seat (I've been on a few with more than a couple) in order to provide frequent enough service to draw traffic overall. Yes, SW is like a bus, but given a choice between 1-2 flights a day on one of the other airlines (probably with out-of-direction travel and one or more transfers) and a direct flight on SW 4+ times a day, which would you prefer?

A classic I had a couple of years ago was a business trip from N Cal to S Cal (Ontario). The company travel agent wanted me to save the company, literally, $20 by using (I forget whether it was American or United), with a change in Phoenix, a total trip time of 6 hours (if everything was on schedule), half of which was sitting in PHX waiting for the connection, and only 2 trips/day. Compared to SW with 8 trips a day and an hour in the plane enroute. For $20 more. My boss immediately took the point, considering my hourly rate, and signed the chit for SW. Note that the airplanes operate at the same speed; it was the frequency that drove the quality of service, with total travel time important but #2.

Delta etc. just don't seem to understand that.