I've been following the bugzilla issue for it for years now but there hasn't been any real progress on it. I don't think it'll happen until we can get it to an interop.[0] Speaking of which, interop 2026 is still taking suggestions[1] and I don't see any proposal for these inputs
[0] https://wpt.fyi/interop-2025
[1] https://github.com/web-platform-tests/interop/issues?q=is%3A...
There actually was some massive progress on it 3 months ago and it looks like they just need testing now but, again, it's just not a big priority
> a big boost for performance (date pickers often load 100s of locales and translations)
The native date/time pickers work great across all 3 major browsers in my experience. The use-cases for type="week" and type="month" are simply a lot less common.