Re: lizards and cold blood.
Nope. The latest scientific evidence is that the Dinosaurs were much more closely related to birds and may even have been feathered. As such they were most likely warm blooded.
If you can demonstrate to me the existence of even one single type of warm blooded lizard, then your hypothesis might be valid.
Until then, it is just a hypothesis. Comparisons with birds or mice or cockroaches nonwithstanding. And the known facts point towards dinosaurs being cold blooded.