|FATE Core made gazillions via kickstarter|
TL;DR it's all perception bias, well spun hype and a modicum of success.
So, I hope I never fell into this trap, but for some people the whole notion of aspect based design is powerful and it actually happens that you (as a budding FATEhead) start to see everything in terms of aspects, positive and negative. This is especially easy when you aren't aware of this being An Old Idea (case in point: Theatrix, Over The Edge, WuShu, a dozen other things that did "freeform attributes"), and FATE Just Being A Fudge Implementation. These things don't weigh in much about what FATE does these days, but it's still a detail that people might miss, so for them FATE is this relevatory thing where finally your imagination isn't stopped by anything but a lack of fate points and compels by a lame GM.
EvilHat also did a decent job at spinning the PR wheel and got a ton of yarn out of it; hence their kickstarter success (and they had prior experience with the Spirit of the Century pre-order thing).
There were also some early successful spinoffs (like diaspora, which I still like very much) which showed that the OGL was not just a nod towards FUDGE but a thing to build on by publishers that want to cater to the "story games crowd" (in the loosest sense). Not all of these adoptions are good but they're made and apparently bought.
A new incumbent in this area seem to be various *World variants which I know none of, but the chatter and energy about them reminds me of early FATE times.
So, in a nutshell, for these FATEheads everything looks like FATE even if they don't play it, and everything they don't play is so far out of what drives their gamer mind that they have difficulty perceiving it.
I think I might add why I am a lapsed FATEhead, because that's my claim to authority: Eventually the uniformity of the rules and the powertelling-induced seeming arbitrariness led to an experience that was less of "playing a game" and more of "making up stuff with friends". The latter can be loads of fun but never generated long term interest in the groups I played with. So we went and played other games, no hard feelings, but it just wasn't our long-term gig. There's a whole discussion to be spun out about unified mechanics vs interlocking various subsystems that change over time (i.e. D&D combat AND hitpoints AND saves AND spells at different levels) and how making them work together is part of the experience that seems to keep up interest longer, but I don't think I can put that into a coherent post / comment just yet.
 In a way FATE is an anti-GURPS here where GURPSheads I know also reflexively start pondering how a certain fictional character would be built or how to model a real life thing ... FATE also brings enough crunch to twiddle these things,
 Sorry for trolling (-: In my experience if you don't have the GM as stern arbitrator of the world; i.e. a referee in the classic sense, the flexibility of Aspects and Fate Points can easily devolve into arbitrary Powertelling (a term coined by a friend for WuShu where you add details not to be more interesting but to add more dice/increase your rate of success). Admittance: I was bad at this because it's a fine line between being stern arbitrator and being perceived as blocking the players' every move.