I'm a big fan of true Bus Rapid Transit for San Antonio, as long as:
1. It's a quality system that actually follows standards for BRT, biggest ones being dedicated lanes, all door boarding, off board fare collections, and level platform boarding
2. It's a significant cost savings over rail
I just don't see SA becoming dense enough over the next 20-50 years to really need the capacity of rail. LA has built their latest BRT project to be able to handle arrivals every minute, so you can just add more buses to handle increased traffic.
There isn't a global qualifier of what BRT is but here are some guidelines that I think are pretty good.
https://www.itdp.org/library/standar...d/what-is-brt/