Those are hard to pull off across a full XY grid as soon as something happens like a line is single tracking or your grid is missing a stations it's a mess. You also really want some slack in the system for cases like single tracking if the average train is 4 cars, but you can send 6 cars trains when demand is up that makes a huge difference.

So, yea that's one way to lower the average wait time, but again just sending more trains and the system becomes more stable.