I still won't blame any OS for it. Everything got really complex and huge the last few years and old hardware just isn't cut out for the complexity. Everything from websites to video encoding has got huge and complex.
Example, I can install quite a few OS's on my Lenovo S10 netbook, they run fine....as long as I don't do anything. Run Plex, the movies stutter. Opens a website, but too slow to process (you know everything need to load one webpage, cookies, trackers, pictures, videos, etc) and not viable. Take it back a few years, this laptop could do a lot.