Marginal changes cut in both directions. The transport duration between A and B is only one part of the calculation. A rider also needs to get from their starting point to A, and from B to their destination.

Decreasing the number of As and Bs by half might reduce that 20% start/stop time by half, shaving 10% off the total time. (This is ignoring the fact that more people will need to board and leave at each stop, which might mean in reality you’re saving like 8%.)

But you will also increase the distance walked to the bus stop. That means battling cars and weather.