The dinosaurs lived in an incomprehensibly different world. From the food and nutrition to the very air they were breathing which we only have vague ideas about. That means the first several generations at the very least would suffer and die from various nutrition, toxicity and environment issues. Even after all that got figured out the dinosaurs would likely have be confined to some small controlled environment righ…
As far as I understand, keeping such creatures alive would require facilities with enriched oxygen. If the large ones escaped, they would suffocate. "...large dinosaurs really required to be living in an oxygen tent. An atmosphere in the neighborhood of 35 percent oxygen would be considerably more compatible with large dinosaurs than one in the neighborhood of 28." Volcanic activity in the Cretaceous enabled these hi…
There are all kinds of animals today we cannot keep alive in captivity because they require some sort of unknown sequence of environmental triggers to activate or deactivate various processes in their body.
For instance cheetahs are nearly impossible to breed in captivity because their mating process requires running for many miles to exhaustion. Without this the pregnancy rate is in the abyss even with artificial methods. There are endless examples thats just one off the top of my head.