Buses are better than rail because they can be changed in response to changing conditions.
This is bunk, and bunk in the worst way. While bus systems typically change route schedules (what time the bus comes) and bus frequencies (how often the bus comes) the rate at which bus routes (where the bus goes) are changed is glacial. Some buses still follow the same routes that trolleys followed fifty years ago.
Any time you try to change a bus line, you will get the people along the bus line coming out in droves. As you would expect. Because you are trying to steal the car out of their garage.
As a renter, it's a lot easier to change where I live then it is to change where I work. Until two years ago, I moved every single year. But I always stayed close to a transit line that took me directly (no transfers) to work.
Making route changes even more difficult is that many of the people who come to the public meeting about the route shift are going to be wretched--old, poor, retired, or disabled. For whom that route is the only form of transportation available, and takes them to critical services--doctors, grocery stores, banks, everything. And they will be furiously angry, because they are afraid that you are going to steal 'their' car.
The funny reality is that most public officials don't respond to public sentiment--they respond to their perception of public sentiment. And nobody wants to be the one who takes grandma's bus away.
Second, I'd like to discuss the idea of 'changing conditions': Conditions don't change. Transit ridership responds to density: Number of people per acre, number of jobs per acre, square foot of retail space. And those change at a pace that is glacial. The build environment doesn't change quickly. Houses last a long, long time. Office buildings last even longer. The hypothetical 'changing conditions' buses are supposed to be able to respond better to? They don't exist. Buses follow the same route trolleys followed decades before because it's still a good route. Still a lot of small houses, 8-12 of them per acre, filled with people still wanting direct access to downtown.