Believe it or not they do, small arms are much easier to get than heavy weapons they also are much easier to use. The cartels ironically rely on a lot of weapons coming in from the US especially as the remnants of Cold War era proxy wars in central and South America die out and they can no longer benefit from both the US and the former USSR dumping enough weaponry to invade Europe into the jungles.
Weapons don’t grow on trees, they are easy to get as long as there are conflicts in the region which are sponsored by superpowers or other patrons with sufficient resources that facilitate those shipments once those end they become rarer and rare.
