what you experienced is normal for these trucks, we see the shocks start to wear out as soon as 80k some go a bit longer. Sometimes people do not even realize the system is not working right and do not even bother to look. When they do then they find it's all blown out. The next gen k2XX are known to be even worse and start to wear out as soon as 40k the front shocks get hard and make a rough ride, the air bladders on the rear start to leak air and then the pump burns up from running so often.
I can definitely feel the difference when it is not working right myself, when it is working right the ride & handling is pretty nice so it's worth it to keep the system instead of trying to defeat it and save a few bucks.