Los Angeles just needs buses that come through frequently enough to obviate the need to check the schedule. Also dynamic bus routing, which would reduce the total number of buses required for this.
Like most cities around the world it really varies by what route and time of day. There’s plenty of sub every 5m routes during peak hours.
Buses have a fundamental speed issue that subways do not because subways do not stop at intersections for cross traffic. At LA's vast scale you need a subway, possibly even express subways.