I was forced to use an old 2011 (IIRC) MacBook Air in 2020 (my replacement BTO MacBook Pro was stuck in China due to the pandemic), and the OS and local apps were fine and reasonably snappy, but oh boy, the web sucked so bad. Slow slow slow. Couldn't open more than 3 or 4 tabs of "modern" websites (HN was fine, yay). Virtually unusable. I was shocked.