It doesn't have to be easy to replace, there just needs to be an intended way to do it. Even if it requires you to bring them to a shop and let them do it (e.g. how most phones handle it). There's absolutely no reason they can't be engineered that way, don't be foolish. The problem is priorities. It is 2020, and some still haven't realized how important these issues are becoming?

Don't want to single out Google, and this little product launch too much, same goes for Apple, and all the others who still think it doesn't matter. And before people say, well the little amount of plastic and metal inside the pods is insignificant compared to all the other stuff we throw away daily, I'd say the message is equally important.

There is no reason to not make these lasting. Only priorities.

Better to pay a 20y to replace it than throwing the entire thing to the bin.

Agreed. Most people can't replace a wristwatch battery, but wristwatches are not considered disposable items. I don't see why similar approach couldn't work here. Non user-serviceable does not have to mean non-serviceable. Unfortunately large companies consider serviceability a bug not a feature, and not enough consumers vote with their wallets to prove them wrong.

A screw and gaskets would keep it waterproof, add little weight and size, and if the screw is has a Phillips head, it will be sufficiently easy to replace.

But, it requires more work to assemble, and does not create an end-date on the existence on the product, so there’s really no reason a mainstream company will do this on their own; they’ll leave it to niche providers.

How much weight and bulk would that add? Not to mention that the battery package itself will need to be larger and more robust. These things are barely small enough to use as it is.