If RSS could solve the problem it would have done so a decade ago.
The core issue is that browsers have completely failed at offering anything to keep track of websites. Why aren't notifications simply build into the bookmark system? I don't need the website to provide that information via yet another special format, my browser should be able to figure that out itself from plain .html. But bookmarks haven't changed one bit in about 30 years, instead we moved that functionality server-side for no reason.
The core issue is that browsers have completely failed at offering anything to keep track of websites. Why aren't notifications simply build into the bookmark system? I don't need the website to provide that information via yet another special format, my browser should be able to figure that out itself from plain .html. But bookmarks haven't changed one bit in about 30 years, instead we moved that functionality server-side for no reason.