Maybe I am good at keeping track of things, but I've never even considered buying multiple sets of headphones (except to replace my current set with a better one). If you don't understand why anybody could spend $150+ on wireless headphones, I could hypothetically answer that I don't understand why anybody would spend money on more than one pair of headphones just because they are too lazy to carry one pair always with them. But of course I can understand it, it is just not worth it for me. It's a shame you are not able to say the same about my preferences.
For me it's more of a convenience. $15 may be an overstatement; many headphones I have spread out at work, truck, garage, bedroom, living room, basement, etc., are "giveaways" I got somewhere and/or those that come with various iphones & ipads. Same for the 1/8" male-to-male cords I keep laying around at the same places for when I need to feed into a stereo other than my JBL Bluetooth speaker. It's not about laziness, it's about convenience. Nice portable phone fits in your pocket....now need to also keep track of airpods/Bluetooth headphones since your many corded items can't be used w/o also carrying around a dongle for charging. Same story from me I know.