> I have seen comments on HN multiple times over the years claiming batteries die in a few years and were almost never downvoted.

Car batteries - very unlikely. Cheap portable electronics made in China - all the time.

The problem with these comments is that there are at least 10 different battery chemistries, and dozens of potential use cases and duty cycles you can put a battery through.

So yes, some combination of that will make batteries die in a few years. Most won't.