Good for you.

no other manufacturer is supplying spare parts for 8 year old models, regardless when purchased.

Cheap laptops from other manufacturers don’t cost as much as a MacBook Pro. And I’m sure some do.

Just because Apple gets its batteries from suppliers in China doesn’t make every Chinese knock-off battery sold in China of the same quality. That’s seriously flawed logic.

I think you overestimate the amount of battery manufacturers in the world.

I think you overestimate your understanding of Chinese battery manufacturers. As in, you don’t speak Mandarin, and probably have zero knowledge of it.

You seem to be the one who is confused, and as if you didn’t read the OP at all.

My issue is that third-party knock-off batteries are usually garbage. Even the iFixit one you suggest. https://www.reddit.com/r/macbook/comments/1237kwd/anyone_ever_had_issues_with_ifixit_macbook/

Plus, that you suggest getting a laptop battery from some mystery store on eBay is just plain bad advice. Even more garbage than the knock-off ones on Amazon.

Minus the battery, laptop works perfectly fine.

I bought it in the middle of 2016, so yes, it’s a 7.5 year-old laptop. One which works perfectly fine and definitely is not “obsolete.” Apple does this mainly because it forces customers to buy a new device. Simple as that.