Have none of these "Airpod leash" developers taken the time to understand how the product works? Not only will the weight and movement of the cable almost certinly cause them to fall out much more often it will also prevent the quick and seamless recharging using the included case.
If you don't want two independent ear buds then you have a plethora of choices in headphones. Why someone would try to shoehorn a different product into working instead of using the correct one in the first place is entirely beyond me.