I don't know about a modern AR type rifle being way ahead of the AK for reliability. Both have strengths and weaknesses.
There are definitely situations where the AR would fair better than an AK. With the much more open system of the AK, it is easier to get crud inside. It is a bit more tolerant of crud, but there will be a point where it causes issues. The AK does handle neglect better... Lack of any real attempt to clean, not enough lube, rust and just being poorly taken care of in general.
For the most part, the AR having a pretty sealed system makes it very reliable when in harsh conditions... But it can be susceptible to fine particulate matter in the air. Very fine powder and sand that is being blown constantly by the wind, can cause issues, as it creeps in. It can be dealt with effectively with proper lubrication. Many tend to think less or no lubrication is the key, to prevent the stuff from sticking to the lube... But generally more lube is better. The stuff is getting in either way, and lube keeps it from caking up to the point of preventing movement. It doesn't like neglect, and a few parts need to be watched, as they need replacing from time to time, like the firing pin retaining pin. But the AR doesn't need to be kept spotless either, you can run one for thousands of rounds and only keep adding lube from time to time to keep it going.
Both are going to have an issue if the chamber gets crud inside. No chamber is "loose", a couple grains of sand are enough to cause issues.
Generally the AR is just easier to live with... A bolt stop, non rock in mags, controls that are easier to use (but not perfect, not in mil spec form)... More modular for modern sights and assesories.
The lack of a bolt stop can be annoying on an AK... It's not an issue on a proper one, as they are meant to be use in full auto, you reload when the rifle stops going pew pew. A semi doesn't have that simple feed back... You just get that click and have to swap mags.