I could go on but you get the point. Services often start out as private entities. Over time some services transition from private to public ownership.
Over time? I'd say immediately when [a] government is formed do the public services (of the type you mention) get absorbed by hostile takeover.
So what is your solution to corruption? Do nothing or tackle the problem.
There is no solution. NONE. Those who govern us are beyond reproach, and getting worse. The taxpayers and their concerns are in stark contrast to the interests of government.