Channelling my father here, but the lessons learned (but not fixed) after Beeching gutted the railways will be learned again here only too late.
That is, once you get rid of the minor bus routes, you'll realise that quite a few people were using those to get to the major bus routes, and now some of the major bus routes are as little used as the minor ones were.
And so you repeat. Close the minor ones. More minor ones. Confused face. Close the minor ones. Customers are complaining they can't get anywhere. Profits aren't rising. Angry face.
Soon you're left with only the buses that run the straightest routes to the closest nearby major places and all you can say is "nothing we can do, it's too expensive to run anything else."