There has been an RFC about it (for years).
"Remove .m. subdomain, serve mobile and desktop variants through the same URL" https://phabricator.wikimedia.org/T214998
"Remove .m. subdomain, serve mobile and desktop variants through the same URL" https://phabricator.wikimedia.org/T214998
It would be considered a non-tracking essential site function value too, so you wouldn't need to beg permission (contrary to what people who want us to be against privacy legislation will claim), and the site is probably already asking for permission anyway for other reasons so even that point is moot.
Or are you suggesting mainstream browsers are blocking same-origin session-level cookies by default now? I'm not aware of any. And if you have a browser that is blocking such things, the worst that will happen is the current behaviour (repeated mis-guesses because the preference isn't stored) continues.
Things you touch regularly should be fine.
And apparently it only affects mass local storage, not cookies which are most often used for season management (so you might stay logged in but the app need to reset data previously called in local storage).
That Safari does this is useful information that I may need to warn users of one of my projects about, as it means intentionally offline data has a much shorter expiry date than on other platforms.
I'm not defending Safari's policy, by the way, just describing. I think it sucks, and a conspiracy theorist might note how it favors native apps over web apps.
It is a work-around improving the UX on the second and subsequent requests, not a fix for the root cause.