The degradation seems to directly correlate with the modern-feel of the page. I'm not sure if that's intentional. It seems that modern front end fashion is a huge step backwards from earlier fashions in web development.
It's completely possible to have a "modern" page that is also nice to use; it's just that with Reddit modernness and horribleness have been conflated together and it seems like they go together.
I don't know what exactly "modern" means here, but I think FastMail, Inoreader, and GitHub should count. All three have been fast and responsive. In particular, switching from Gmail to FastMail was a revelation.
Random aside: I've long been very down on web tech, but those 3 have sort of reinvigorated my interest in web stuff.
Do you have any examples of this? Every 'modern' webapp I can think of has been an exercise in making it slower and more confusing than its old-fashioned predecessor. Especially slower. They're _so_ slow.