Kicking on the same side a straight punch is coming from is an obviously effective counter, just because kicks, and long knees are in play doesn't mean the punching element of muay thai is obsolete and should never be used. There's a counter to nearly every strike including the teep, getting dumped on your ass is just as unpleasant, does that stop you from attempting to establish the teep? Or do you instead use context..when the opponent is advancing for instance you have a great opportunity to teep safely (as one example). Similarly the long guard is a tried and true staple in muay thai and makes one vulnerable to kicks on the lead hand side as well yet it's been consistently shown to be used effectively by good fighters especially Thais. The beauty of jabs is there are multiple ways to throw them, multiple reasons to use them, there's no reason you have to be throwing weighted front foot heavy jabs all the time to make you vulnerable to leg kicks. Are leg kicks an obvious counter to someone coming in front foot heavy with punches? Obviously but again it goes back to my first point. You can also target any area you want with a jab if you're doing so correctly. A well executed, properly weighted jab can also make your opponent gun shy (both with kicks and punches). I'm not advocating for being a dumbass and blindly wading in while your opponent happens to have an obvious kicking advantage over you, but to use that as a reason to neglect the jab and in my opinion hurt the setup of your punches, kicks, knees, elbows, and make your distance management less efficient seems shortsighted to me. Lastly there are different stylists within muay thai and kickboxing, some nak muay are more punch oriented, or kick oriented, others more knee/clinch oriented as was the original context of this thread. We can disagree on the importance but those are my reasons with all due respect.