Routes should not be created or changed often. People need to rely on transit, if they can't be sure their route will still be there for long they should buy/drive a car even if there is good transit today since they will need that car when the routes change to something that doesn't work.
changing routes is needed of course. Cities chanre and you need to follow that. They don't change fast though. long term routes also drive change as people adqust their life to what they can do.
I went down a rabbit hole a couple years back, and it blew my mind to learn that many modern bus routes just replicate streetcar service that was discontinued (and the tracks torn up) 70-80 years ago.
That isn't a surprise as people build their life around what they can do. If can make a trip they will and so those routes tend to stay useful/busy. There are sometimes better routes we could use instead today, but often the existence of those routes 70 years ago set how the city grew and so those are still useful routes.
changing routes is needed of course. Cities chanre and you need to follow that. They don't change fast though. long term routes also drive change as people adqust their life to what they can do.