The thing is, the government's incentive is providing a service good enough to keep them elected. The private company's incentive is getting the most money possible for the minimum service possible to maximize profits. Of course it's gonna be bad, because such is the nature of capitalism
When the private company owns the government, it is in their interests to maximally loot the public purse in the first term because the chances of a 2nd term fall sharply when the rubes wake up, and if they DO get a 2nd term, it is in a place too stupid to generate ANY profits
Where I live, they privatized electricity. Their service is known to be awful, power goes out all the time and they only fix it quick if they're loosing money with the problem, which means you're screwed in rural areas. Meanwhile, the government would fix as soon as they could regardless