That's the whole point... there was once a bar that set some sort of quality within the genre. Of course, the birth of those great films also brought with it the onslaught of those trying (to this day) to recreate them. Not recreate in their own way, but in the same was as the originals. For me personally, the only films that have come close to actual entertainment and some grain of quality are those that ARE self-aware of what they're doing. By that I mean the whole of Grind House(both films) and of course the awesomely bad Hatchet. With Hatchet they completely made fun of all the original movies that boasted the same theme, mysterious undead killer in the woods, slutty topless girls, and bad bad acting/writing. There were some great gory moments in the film, but anyone who thought that movie was trying to be serious, seriously missed the point. Then you have movies like Saw, Hostel, etc. who say to you "we really did try to make the acting decent, the effects gory enough to one up everyone else, cinematography, etc" and yet it still comes off as a limp dick of a horror movie. These are of course only my opinions... and I'm sure I'll get LOADS of crap for this... but Blair Witch was a movie so many hated... but as a fan of the genre, it was nice to see the cgi not trying to outdo everything else, the acting coming across as more genuine, and completely cooler to not know what the hell exactly it was I was supposed to be afraid of. I hadn't seen anything like it in the theater in a long time and since then I don't think I've seen anything to rival it. Anyone who makes as much money off of such a low budget movie as they did, has to tell you something... people are starved for something new and more than that, willing to pay for it. But like all movies that make loot, there have been since, probably 20 different rip off movies... one off the top of my head, Sector 9, which was of course... awful.
Sorry for the long rant...