I am not here to argue for a "side", to win an argument, nor provide a thesis defense with citation and references -- this is an answer you can easily get from ChatGPT. There's quite literally hundreds.

To add a wrench to both "sides" some of the most effective have been state/federal-owned /state/federal controlled corporations -- or generally, arrangements where you still maintain capitalistic economic incentives and drivers, but have government oversight and (effective) regulation. I think everyone would that is good, but sometimes it takes different forms.

Then let me restate, this is an area where you can easily wade along with largely inaccurate information quite easily. I also wasn't necessarily trying to bait you to give a list, though it would be interesting to know which ones you have in mind, specifically. Far too many of us don't have any evidence, we have been duped by trusting that others do.

I took your specific claim to be privatization of government functions having many success stories. I'm still curious which ones you have in mind, but would more largely be interested in studies on this. Nothing wrong with knowing the wrenches in there.

Beside that, though, I was trying to engage your question. The difference is if growth is privatized into a few, or if it is more broadly available. With a large agreement from me that a mixture of both -- your wrench, effectively -- is fine. Good even.