Nah, its more about how WOTC made a mess of 4E that led to a portion of DND core players moving to the back then the ONLY supported 3.75E in the market
, some of them permanently.
(Just look at that sharp upturn once 5E came out.)
Though arguing which one's "better" had always been like arguing about whether Coke or Pepsi's better...
But the ranking wasn't all that interesting. What's interesting was how the trends changed in that short period. (If you considered that before 2004 DnD/WoD/GURPS had been the permanent Big 3 since forever, the past decade was indeed an interesting time.
And also that FFG is really
Mongoose at 2004 was going with Conan d20 which was well received, as well as picking up Paranoia. It's probably mostly about Conan though.
Green Ronin was mostly about True20, and should've been using the same line with M&M, but they were kinda winding down already. (Anything after that period of time were only DCA & M&M, and both were pretty much the same game anyhow. F/DA was kinda surprising though as there didn't seem that many people actually playing it... VideoGame-linked effect?)
......Waitminute. What's flicking Iron Kingdom
doing on the chart???
(Oh right, the 40k TWG>RPG bloat thing...)