Because if that would work, then we would have it.

And the USSR did use nationalisation during their wartime reconstruction efforts, in which a destitute third world nation became an industrial superpower within just 2 decades.

The collapse began following the Perestroika era, in which they reverted back to the old system of free market liberalism.

So you're right, and it's a perfectly reasonable concern. But there is a bit of historical context to it as well.