The fact of the matter is, the army gave up Maduro, that the US wouldn't have attempted that op without buy in from venezuela's military. Helicopters are vulnerable to multiple ground based weapon systems the US couldn't reliably take out.

The Venezuelan civilian leadership has since ousted many of their generals, probably because of this fact.

They are far from controlled by the US, and it's a very large country, near 30 million people in a massive area, larger than any State save Alaska, which is around 500k square miles while Venezuela 352k. Much of it mountain and jungle, (makes it harder to stamp out resistance.)

All the US did was pressure their military leaders to try and coup them, then seemingly failed to back up the coup. We are forcing them to sell their oil to whom we say, there is that. But that is about the extent of it at this point.