That renders the AirPods difficult to use for noisy urban commutes (where you're
likely crank up the volume to unsafe levels to compensate), and it also leads to people just leaving them in at all times, which is irritating to others.
It'd probably result in a price hike — or, more
likely, some sort of «premium» model — but the AirPods» unsealed design lets in a good chunk of noise if you don't
crank the
volume all the way
up.