Lanefan
Victoria Rules
I hear my name being taken in vain... 
That said, in a hypothetical situation where Fate (or any other single system, for that matter) was the only game system available, a dedicated GM could and would houserule and kitbash and squash that system into providing whatever game experience was desired. Sure they system might fight back for a while, but IME GMs always win those battles in the end.
Cheaper, too.

About all I can say to this is that if Fate can't do all the things @Aldarc says here it can't do (an assertion I have to take on faith as I'm not all that familiar with the Fate system) then it's probably not a game I'd be interested in playing.And I think that a fairly good way to highlight how people cannot do everything with Fate is to summon @Lanefan, with whom I had many prior discussions about how the Fate system is not conducive for telling the same stories he prefers. Fate is not designed for many of the things that Lanefan wants out of his game. Fate is not designed for zero-to-hero narratives. It's not designed for exploration and dungeon crawls. It's not a game about rewarding good tactical play, players engaging an in-universe resource management minigame, or solving puzzles. And sort of the action declarations that a player can make or encouraged to make will differ between games. (@Lanefan has expressed similar issues and reservations with games like Dungeon World and Blades in the Dark.) You really can't use Fate to run D&D style fantasy, though there are supplements that try, including the nearly ubiquitous Freeport conversion.
That said, in a hypothetical situation where Fate (or any other single system, for that matter) was the only game system available, a dedicated GM could and would houserule and kitbash and squash that system into providing whatever game experience was desired. Sure they system might fight back for a while, but IME GMs always win those battles in the end.
Perhaps...but the flip side is that it's almost always far easier, both for GM and players, to adapt or modify a system you already know than to learn a whole new one.My experiences are circumstantial and anecedotal. I can freely admit that. But through those experiences I have often found myself repeatedly engaging with people who wanted to create/convert/adapt something for 5e that required changing 5e to do something cumbersomely that it was not really well designed to do and where other pre-existing systems tended to do better at that very thing they expressed wanting their 5e game to do.
I don't think there would be much opposition to the idea that if someone, for example, wanted to run a game that simulates an investigative Cthulhu story for 5e, many on this forum would probably first propose that they consider using CoC rather than adopt that for 5e.
Cheaper, too.