Cost and lack of skilled workers. Fabs cost billions to build, then you need to have lots of guys working there who have lots of knowledge and experience.<p>The difficult part about bringing manufacturing back to the US is not the cost of rebuilding the factories but the loss of all those skilled workers over the last 30 years who have retired, died, or been retrained, or just plain old forgotten what they once knew.
The major concern is what if government-funded industry such as this succeeds, thereby encouraging more of it, the slippery slope to state capitalism and then Marx. The term escapes me, but it's some sort of neoliberal woo woo I can't quite remember. It does look rather iffy when you're whaa whaa'ing China for its state-funded industry when you're state funding industry, in other words. <i>Socialism bad. Cooties! Everybody run!</i> All that jazz.