The cold v. warm blood thing is far more complex. For instance, warm blooded animals can handle slight changes in temperature better than the cold blooded. A wolf's reproductive cycle may be tied to the weather, but a degree or two either way won't really impact the development of its live young. But a degree or two for a croc egg and it might not survive. Or all the crocs one year are male because egg temperature can impact sex selection. If a meteor causes havoc with the climate, that warm blood under some warm fur could be a real advantage.
Oh, to clarify, when I talk about that, I'm not talking about temperature tolerance - that's really more of a secondary byproduct - but metabolic demands. A warm-blooded (i.e. fast metabolism) animal needs an order of magnitude more food than a cold-blooded (slow metabolism) animal.
That too is more complex. An animal like a bear does need more calories, but being warm blooded allows it a greater endurance. A bear can travel further to find food. A bear can access calories over a larger patch of land, and during a greater number of hours each day, than a cold blooded crocodile. So a bear might survive in a more calorie-depleted environment despite its increased appetite.
From what I've read, dinosaurs were not warm-blooded due to their fast metabolism (endothermic) but due to their size and associated heat capacity (homeothermic). That would have made them relatively less susceptible to starvation than present-day mammals, but given their size, they would still require plenty of food.
The big ones. Most were not the movie giants and so were probably much more coldish blooded. It is all a bit of an oversimplification. Some big fish (white sharks) can have internal temperatures a few degrees above water temp. There are all sorts of middle grounds between warm and cold blood.
