I guess relying on capitalism to build a country would fail if foreign countries could just buy out your most important companies.

The premise under Capitalism would be that the state-sponsored / state-owned corporations were acting as conquering agents and should be treated as a form of invasion in terms of national defense. The theory is that it'd be defending the rights of the people to not be brought under the heel of a conquering foreign government. Such trade would be regarded as a military action on behalf of the foreign country, since under Capitalism the government has no role to play in the economy in terms of owning & operating economic assets.

This has been false from the beginning though, you are referring to an imaginary capitalism that never existed.

It's too late for Europe. Open a VDSL FTTC cabinet or look at CPE and OLTs and ONTs and it's all Huawei/ZTE crap.