Demonstrably untrue, if you were to look at taxis, ubers, lyfts, and ... small vans that operate exactly as you describe, in many large cities. (In NYC, I know there exists such a van network in Brooklyn, and near the George Washington Bridge running across the river.)
And besides, buses have advantages that "intelligent routing"-based vans - predictability and reliability. If I need to get somewhere by bus, I know exactly which stop I need to go to, and usually when the bus is scheduled to arrive to pick me up, and also to drop me off.
(Granted, sometimes those times aren't right, but they usually are, most of the time.)
Smaller vans, transporting several people at once, are also busses. Any and all private competition offering to transport several people at once, would also use vehicles colloquially called busses.
Furthermore has public transport historically never been for the convenience of the people. Instead it provides jobs, increases the flow of money, provides income for The State.
You can read more about the beginnings of public transportation here:
https://www.perplexity.ai/search/hey-hey-can-you-tell-me-who...
Where I live the busses are quite useful and get used by a lot of people.