Because making it work well costs more than making it work barely, and those costs are ultimately profits not being paid to shareholders now.

Those making the decisions get paid their bonuses based on the now, not the maybe, in the future.

It's really that simple.

Stuff like infrastructure should most of the time not be privatized and remain in state hands.

As a business you just need to outbid your opponent for the electric grid or whatever. Then you do the bare minimum to say you delivered within budget etc. People are sheep and won't notice until they are sitting in the dark.

The company that had a realistic cost in their offer was probably not picked.