It broke absolutely no new ground. It just did mediocre things in a slightly better way. Slightly better characters, slightly better writing, slightly better graphics.
For context, it comes from a time when folklore was considered a good game, such was the desperation of ps3 owners to have "something to play".
It was just "ok". Luckily uncharted 2 stepped everything up to become a pretty good game.
Come on, that's just not right.
Folklore is a 75 MC game (EDGE 5/10) with mediocre sales, Uncharted: Drake's Fortune is a 88 MC (EDGE 8/10) multi-million seller on a early userbase; it was both critically and commercially successful that warranted launched the seeds for one of the strongest Sony IP. Stuff like Folklore was none of this.
Now sure, even though it was Uncharted that got the ball rolling for Uncharted 2's hype, Uncharted 2 was such an improvement in every way (from a 8/9 game to GOTY-level), that, by that time, as PS3 sales were on the way up, a lot of Johnny-come-latelies picked up Uncharted 2 first, and of course, the hindsight side-by-side comparison wasn't favorable to Uncharted, so it became common-place to say Uncharted is not good.
But we still can't rewrite history because the proof is in the pudding. Uncharted faced a lot of hurdles, from PS3's convoluted architecture and development issues, to Naughty Dog taking the leap of faith to a whole new type of game they were inexperienced in; nevertheless Uncharted was still a wonderful pulp movie - type gaming experience with fun set-pieces that right from the start gave the impression that with some polish it could become a multiplayer game as well - and so it did. Which, btw, was still a heated topic because there were a lot of Uncharted fans that were claiming the game didn't need multiplayer. Yeah, the game had already earned a certain status by then.
So yeah, it wasn't like an obscure game that got unwarranted love before falling into obscurity. It was the beginning of a strong franchise because it was well received on all accounts. It was a risk that paid off handsomely.