Part of the conventional wisdom about transit which prevents spending real money on quick headways is that “There’s no market. People aren’t using that route. Why should we be running empty buses?”
My quick answer to that old saw is that just as with roads, with transit, supply induces demand. If you offer a rich ‘connection pipe” (to garble Walker’s terminolgy) then people will use it and people will get used to the service and presto you have political support. People support things (politically) that they use.