What you're describing looks less like "we tried protectionism and it failed" and more like "we don't have institutions that can reliably carry long-cycle industrial projects from idea to operation."
Protectionism was tried & has failed in other industries, most notably U.S. shipbuilding.
The Jones Act is arguably why China's Navy will soon dwarf the U.S.'s ancient fleet.
Exactly. This supply chain requires four quite different plants, none of which make money until the other three are running. US capitalism isn't good at setting that up from a cold start. Market forces may get there incrementally, but it takes a decade or two. It's high risk for any part of the chain to get ahead of the others.
China's industrial central planning has no problem doing this. Where there's been progress in the US, it's been because big customers, DoD and General Motors, pushed.
This is a nice example to look at closely. People in US politics have been screaming about rare earth problems for a decade now. It's not a resource problem. It's a capitalism problem.