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.

Cars are the least efficient form of mass transit yet devised. They take up inordinate amounts of space to move very few people. This creates unavoidable congestion problems at very realistic levels of urban density, problems which are only solvable by enabling people to use viable alternatives.

This is why the subway and buses in Manhattan move 5x and 2x more people respectively per day than cars. (https://new.mta.info/agency/new-york-city-transit/subway-bus...) (https://www.reuters.com/world/us/manhattan-drivers-face-9-fe...)

Speaking of "wasting life in buses", did you know that the average LA / Chicago / NYC driver spends 85 to 100 hours a year just sitting in traffic? Food for thought (https://inrix.com/scorecard/)

For certain high frequency routes in Chicago, I never minded sitting on the bus to get across town. At least once I got off I didn't have to find a parking spot. Now wasting life waiting for a bus is another story.

And that’s leaving aside all the issues with our of control transit budgets or crime on public transit in many cities.

As it stands they're already maxing out and exceeding (when they're late) the max speed for the class of rail they have.

Some of the inner stops might get a few seconds faster with better acceleration but that's about it.

The grade crossings are also kinda f'd. At full speed you can be in the middle of the train and see the arms still be in the process of lowering at certain crossings. That ain't safe. Faster won't make that better.