LOL! You ALL are waaay off...lemme tell ya what really happened:
Dinosaurs are still around. They are, eh, just invisible! Umm, yah, that's it. And, and, well see, only Steven Spielberg can see them. So he asked George Lucas to um, use his demonic powers at Industrial Light and Magic to wave his magic wand (get your mind out of the gutter, not "that" wand) and they appear only on movie screens, lunch pales, and assorted action figures at your local TARGET. See, the dinosaurs were smart, they wanted to wait in their invisible state untill someone could launch a highly profitable marketing franchise on them. And that's the "truth". It's all bible based too.
Seriously, I remember in the mid to late 70's the explanation given by John/Jane Doe Witness was; Dinosaurs were destroyed in the flood of Noah. Oh, by the way, ignore all the rest of that other "scientific" evidence...it's evil...EVIL I say!
or another answer:
Shouldn't you be more concerned about other stuff, and wait till the new system to ask those questions. (My favorite, side-step-the-issue-Jw-style-Dosi-Doe. Fun to dance to with square dance music.)
I've studied the astroid, disease, and natural selection theories. And they are just that theories. I just know one fact, it wasn't no global flood that wiped them out.