I don't think they're made to be replaced, it's more a side-effect of the battery being smaller and more susceptible to wear. The original airpods I got 2 years ago still work for about an hour and do fine.
In 2 years the battery life fall to 1 hour? This is just crazy unsustainable!
I'm just surprised I've never run them through the wash.
Please take into consideration that making something replaceable means (in general) adding more stuff to the product. I doubt at this scale that is it possible to maintain the small size and to also have replaceable battery with the current hardware capabilities.
Is "this" referring to "Apple Airpods" or "free market capitalism"?