Don't claim something you can't back up. You don't know "if 80% of people still play 1.8" Period.
Only claim something, if you can back your words. I won't be saying, that majority of Minecraft players would be playing newest version(s), but it's even more stupid to claim, that 80% of people are still playing 1.8.
In fact, the majority of players aren't even playing on the Java Edition, which has been a minority of all sales ever since 2012, and is the only edition to have the 1.9 combat (it is pretty obvious that is what is implied by a refusal to update past 1.8):
http://www.gamesbrief.com/2013/01/minecraft-grosses-over-250-million-in-2012-but-which-platform-dominated/ (note that PC was just 16% of all sales over Christmas; even over the entire year it was only 28% and this was when only a few other platforms existed and they were very new).
Never mind that around 50 million people, a third of the total, have bought the game since 1.9 came out.
Yeah, a third of all servers are on the latest version - 1.12.2 - and over half are on 1.12.x - so much for "80% are still on 1.8.x" - and for singleplayer the percentage is likely much higher (there are many reasons why servers may be behind, like mods and plugins). Just one out of thousands of listed servers is on 1.6.x, so the fact that I still play in that version, and not only because of mods (which that one server most likely is) makes me truly unique. Likewise, most of the 1.7.10 servers are almost certainly modded given the (declining) popularity of mods for that version.
Also, the fact that Java has become such a minority of sales leads to the fact that many people specifically refer to this version when they say that Minecraft is dying but I do not see any indications that it is; it is still selling at more or less the same rate it has since the official release, if not earlier with close to 28 million copies sold so far (which again, a lot have been sold since 1.9 and anybody who bought the game since then never experienced the "old combat"). Part of the increase in the rate of overall sales is due to the game coming out on so many different platforms, and mobile games are simply the most popular these days.