You are right about the battery, it will indeed require a new battery but they could built the headphones in such a way that the average consumer can replace the battery. I am not going to buy the AirPods or Beats as a matter of fact. There are 3rd party solutions that are cheaper and don't have wires. I also hate wires hanging around to be honest.
They could design the battery to be replaceable if they wanted, but if you look at teardown guides they go way out of their way to make it impossible to replace the battery without destroying the headphones. Of course those tiny airpods are always going to be difficult, but something the size of QC35's has plenty of room for a battery compartment. Instead it's full of glue and a whole lot of stuff in the way. On their customer service site, Bose also has a major campaign against anyone even bringing up the battery issue.
I'm a lot less familiar with beats, but I do know they don't want you being able to change the battery either.