Peter Haenseler (whom I normally don't even mention because he doesn't link to or otherwise cite any sources) presented a fascinating hypothesis to explain why Trump stole Venezuela:

The world is selling US bonds and America is running out of money – it's as simple as that. With the oil that the Americans want to steal, they will once again have assets with which to refinance ailing America. Trump was therefore forced to carry out this raid, because otherwise the empty coffers in Washington would blow up in his face. Being a businessman, he even found a way to make his friends in the oil business rich at the same time.

He was also able to rely on the corrupt military and business leaders in Venezuela – even Maduro's bodyguards abandoned him. The military, probably in consultation with the CIA, shut down its own air defenses to guarantee safe passage for the robber barons.

The parallels with Syria are obvious, with the difference that Assad smelled a rat and had himself flown out by the Russians.