After a while, certain high usage routes will be noticed in the rideshare data. It will become obvious which streets and destinations could be optimally served with high capacity buses. Now is the time to bring in bus routes. Setup these bus routes and offer a discount for using them.
The current system isn't working, we need to try something different.
As far as I can tell many people are using public transport, including buses, so it seems to work to some extend.
You can't force a top-down solution for public transit with the road system in the US. The great strength of the US road system is point-to-point transportation. Let everyone benefit from that instead of running buses that only the poorest use. Publicly funded rideshare is the way to do this. After a while, the bus routes will naturally appear in the data. This is the bottom-up way to build a bus system.