Like how server hosting at scale in a datacenter is cheaper than running your own datacenter? Despite ~every company consistently concluding that hosting their own stuff is several multiples cheaper?

No, I think local stuff using also-useful-for-other-things hardware will vastly undercut cloud hosting when the free money pipeline shuts down, and will stay that way for roughly forever. That doesn't mean cloud stuff isn't useful, clearly it is, but adding another company in the middle is rarely the solution for reducing costs.