Most people probably wouldn't want to refresh an SPA like Gmail every time the favicon isn't showing the correct unread count. But for infrequent rebranding, I agree with you.
Yes, I'm not trying to address the feature of having animated favicons or favicons set dynamically using JS. I'm just trying to address the problem of favicons apparently being very stale. My question is why Apple couldn't fix that problem, which is not at odds with Apple's stance against animated or dynamic favicons.