These things have usable lifespans of about 2-4 years before the batteries start to go (depending on how low a capacity you can tolerate). It’s more like you buy the one available at the time when your old ones wear out.

I don’t know if I just got lucky or what. But my AirPods Pro (1st gen) just finally crapped out last week. And the batteries are mostly fine: the speaker blew out in the right one, and it now sounds awful. But that’s ~6-7 good years that I got out of ‘em.