The original idea of doing it privately was that free market will compete for best solution at cheapest price but many, many, many projects later it ends up not being cheapest nor best, just ones that can navigate the politics and red tape best. And that before any kind of corruption gets involved.

It also gets very silly, like one public one that company I work won was literally just iterating the company that currently hosted their infra infrastructure, so the previous company automatically checks all the boxes and any new one have to fit that, and it went to silly degrees like describing clockspeed of CPUs that have to run it. We just gave them older servers that happened to have higher clocking CPUs so the requirement backfired badly on them.

And that is not even neccesarily malice on their party, they just didn't wanted to go thru PITA of migrating everywhere just because some pencil pusher required looking for vendors every few years "in case it will be cheaper".