According to httparchive the average size of a web page in 2016 was around 2.5MB. Now this may not seem a lot in this age where the internet is the primary media delivery platform - but it is worth noting that most web pages serve text as their primary content. Looking at the report sheds light on what constitutes an average web page:
The HTML content takes up around 50-60kB. Images, understandably, make up the biggest chunk with ~1.