I felt OP was suggesting that a European manufacturer would have flourished if properly supported by a visionary government, and I think that argument is mistaken.
You are arguing that globalised supply chains are risky, which is something I can agree with. If europe protects its DRAM manufacturer it is going to be less reliant on China but we should not confuse that with the European company flourishing. It seems likely such protection would be an expensive venture which absent any global conflict would produce more expensive products and make a loss while doing so.