[Night_Thastus]

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.

[landl0rd]

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.

[Night_Thastus]

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.