Chapotraphouse

the TLDR is that Russia doesn't have the capacity to throw sophisticated air defences, let alone Oreshniks, at anyone who might be at risk of Imperial fuckery.

Plus, as we've seen with VZ, sometimes the best radars and export-controlled systems aren't even a passing threat to the empire. If Venezuelan systems engaged with the US they'd be flattened without much chance of a hit, so most of 'em (sensibly) stayed offline, or were forced offline due to SEAD/DEAD.

However, those systems are still a deterrent to imperialist lackeys that might take advantage of instability, and field much older weapons (like the middle-aged F-16s that Argentina got recently). The US would much rather have some proxy do the killing than risk the blood of its jackboot thugs.

SAM batteries don't seem like a good investment for Venezuela. The Iglas actually did MORE to scare American pilots (esp. if one did get damaged as Trump claimed) than the S-300s, and those are cheap to stockpile and potentially easy to manufacture. Realistically there's not much that will deter US air power, so cost-efficiency is your next best option.