That one bus company in the nearby city that absolutely refuses to replace their miserable old buses 🥴🤡 while the others run modern air conditioned hybrids, and some fully electric
Multiple bus companies can be a good thing if done well. The busses in Taiwan are also privatized and the service is quite good. In Japan even the metro and rail networks compete in a private market.
When you privatize a company and make it a monopoly though you get the worst of both worlds.