The dinosaurs got lucky

lostexpectation

http://environment.newscientist.com/article/dn14709-climate-change-gave-dinosaurs-a-lucky-break.html

Moreover they also found that the crurotarsans also developed a much broader range of body types than the dinosaurs.

An observer comparing the two groups in the late Triassic would have expected the crurotarsans to eventually dominate, says Brusatte, now at the American Museum of Natural History in New York.

you can never have enough reports that the many type of creatures way back when not just dinosaurs.

Galvasean

Makes you wonder what kind of creatures would have ruled throughout the Jurassic and cretaceous had the crurotarsans prevailed rather than the dinosaurs.
There could be more than meets the eye to the dinosaurs success though. I doubt pure luck was the deciding factor. I'd say some form of dinosaur physiology gave them an advantage during the mass extinction, possibly a warmer metabolism than their evolutionary rivals.

richie_os

This is interesting