It's not the quality - I am happy enough with the quality of a good bluetooth or Lightning connection, it's the actual connector that I have an issue with. Over the years headphone cords have gone from something you plug into your amp at home to a portable device that is often found in pockets. Headphone manufacturers have adapted and have created right angled plugs, or those that are very flexible as they exit the phone. Combined with the sturdiness of the 3.5mm plug inserted into the phone this made breaking the leads near impossible when put in a pocket and having lateral force applied to it
Fast forward to the Lightning connector which is huge, long, and not very sturdy. Applying force will easily snap the connector in the phone, and possibly damage the phone in the process, I have seen a minor news report already about people breaking the new earbuds, but cant find anything much from major news organisations, but it will happen.