The problem is that it's quite hard to gauge how often a post is red across multiple front ends, steemit did it because at the time there was basically only one front end. Now we have lots of readers on eccency, hive.blog, peakd, so if we were to display a page viewer feature, it would be per front end which wouldn't be very accurate.
We could have it at the api level where front ends could note whenever someone requests to read a page, but first it would easily be gamed and second sometimes posts are loaded even though they aren't red, some front ends load posts just to show the first 5 lines to incite people to read them.
I had no idea it was that complex, but I am surprised and appreciative of the fact I even got a meaningful response. I never really devoted much time to the question posed as I wasn't sure my reply would really get looked at. But, I will now have a proper think and perhaps come up with a better idea that is innovative and unseen elsewhere - and hopefully not quite so complicated or risky to implement.
No pressure :) it's okay to not have an idea in the moment.