As mentioned in another comment, zip support actually goes further back as far as '98, but only Windows 11 added support for handling other formats like RAR/7-Zip/.tar/.tar.gz/.tar.bz2/etc.
That allows it to be a default that 'just works' for most people without installing anything extra.
The vast majority of users don't care about the extra performance or functionality of a tool like 7-zip. They just need a way to open and send files and the Windows built-in tool is 'good enough' for them.
I agree that 7-zip is better, but most users simply do not care.
Windows zip is not in fact good enough. I've run into weird, buggy behavior, hanging on extract, all sorts of nonsense. I can see the argument that a universally-adopted solution is better, but that's different from windows just not working.
I'm not saying I would ever use it. I'm saying that for casual non-power users, it's good enough. They work with it and if it breaks once in a blue moon they don't care. They just want it to open the files they get and give them a way to send files compressed.
That is enough to bite into 7-Zip's share of users.
