GURPS is not better than a role playing game specifically tailored for the setting.
It shouldn't be, anyway.
It's the embodiment of the original phrase, "a jack of all trades is master of none, but often times better than a master of one."
GURPS turned out to be better at Twilight: 2000 than the 1st or 2nd editions of those rules.
GURPS and Traveller work great! Enough that they even made two official versions of it.
GURPS is proving to be OK at fantasy settings, but it's not D&D.
I still want to do AD&D with GURPS just to prove it can be done, but it's significantly more effort than just playing the original game. Magic gives you wizards, but doesn't really give clerics, druids or illusionists. I'm on the path to making that work.
GURPS: Old West is vastly superior to TSR's old Boot Hill.
GURPS: Espionage works a lot better than TSR's Top Secret.
GURPS works well to replace just about any genre specific set of rules where those rules are poorly designed, like a lot of the games from the early 1980's.
What GURPS sucks at is attracting new players thanks to people who are terrified of math and the complexity inherent in a system that's trying to account for everything.
And it's much simpler than Hero Games attempt at the same thing. Or Chaosium.
I keep trying, and failing, to convince people.
I've noticed that once they're playing, it's the GM and the world that make or break the game, not the rules.