I get antsy when I made a page over 100KB (excluding images, and even then anything over 1MB starts to feel excessive unless it's something particularly reliant on images). 5MB feels very high.
Fetched the same on the AMP Cache: https://www-fool-com.cdn.ampproject.org/c/s/www.fool.com/amp... 200KB cold cache. Removing the likely cached resources (amp javascript, fontawesome cdn font) and the payload is ~35KB.
It's certainly possible to make a lightweight page, as hacker news is a great example, but people aren't doing it. For whatever reason, AMP seems to be effective at making the web actually follow best practices.
Then those best practices aren't very good. In my experience, AMP is, on the whole, a detrimental thing that degrades web pages.
All I want is some way of telling sites to never give me an AMP page.