OPEC and other market/supply manipulation, plus collusive behaviour explains pricing more than availability.

Why would anyone exploit thick, heavy, sulphur rich expensive-to-extract oil over light sweet crude? Oh right: Tar sands. Like, this hasn't been a thing for ages.

TL;DR It's politics, its bullshit. Oil is a great feedstock for drugs, fertiliser, plastics and explosives. We don't depend on it for fuel as much as we used to and we will depend on it for fuel much much less in the future.

Venezuela's problems are going to take more than US market manipulation to fix.

(we do obviously both depend on, and need continuance of access to oil, and oil prices affect inflation and industrial production in all kinds of ways. "less" is not none)