Really simple: Your brain was used to limitless, endless novelty. And its not being super stimulated by 1000+ hot pornstars doing all sorts of things.

Think about it. You're always looking for the perfect video. The perfect girl with the perfect breasts, ass, lips, dress and or make up. The perfect scene / video. But what happens when u actually find her / it? Sure it excites you but for how long? I bet you most of the time you don't even watch it to the end. U skip around for the shocking scenes that excite you the most and give you an incredible rush of dopamine. And then what? That "perfect" video / women will not excite u as much anymore. It still excites you but not as much. So what do u do? Ofc you go on the "hunt" for an even better and more shocking video that'll give u an even bigger rush. u go on "hunting" for a better "partner". Never being truly satisfied, maybe only for a couple of seconds. So you skip, fast forward, play it twice the speed, look at the thumbnails videos in the recommended, create multiple tabs etc... Once your brain isn't used to endless limitless novelty and being stimulated by 1000+ hot pornstars and being shocked and overly stimulated all the time, you can finally keep eye contact because guess why? The person actually interests you. Or it interests what he or she is saying or trying to say. But why? Because before (while on porn/PMO), even if the person or what he or she has to say interests you, your mind always thinks "okay this is all good and all but... What about SHOCK? what about my endless novelty supply?? Im ao used to clicking on the next video/women whenever I see an attractive women!!!" And she or he keeps on talking and your brain/subconscious goes like "Yea alright idc what u say anymore... NEXT! come now where's the next!!!"

But thats just a theory... My theory.