Remember... there are multiple elements to a web page. There is:
The base page itself
Images
Stylesheets
Javascripts
For example the forum homepage on this site...
There are over 50 objects on the page. Each of those objects could potentially be served from cache... not just that very first base page.
Now... with that said, in addition to each object, there are hundreds of points of presence for Cloudflare. Chicago, LA, DC, Paris.... each location has its own cache. So an object might be in cache for a user in Chicago, but the first time it's called out of Paris, it is missed so it has to go fetch it and store it. (Meaning the next one would be a hit.)