And if you look to places like Meixco City and Bogota, their bus rapid transit is very fast and efficient. But good luck taking away a single lane of traffic for dedicated bus services anywhere in the US.
This road right here in a west coast US city used to be four lanes of car traffic (two in each direction), but two (one in each direction) were taken out and dedicated for bus service.
According to Google street view, the road had 3 general car lanes per direction up to and including Nov 2016.
Shortly after, the middle lane of each direction became a bus-only lane, but this was implemented with temporary road modifications. (So each direction has 1 bus lane and 2 car lanes.) The middle part of the road was rebuilt from 2019 to 2020, making this feature permanent.