No one is arguing that Steve Rogers could be a real guy. The entire argument is hypothetical and also is built in science if you actually bothered to know what the science is.
We are talking realm of possibility, not realm of reality.
What you are doing is that guy when people are talking about how to bring back non-avian dinosaurs and discussing the possible science behind it going "It isn't based in reality whatsoever." All it shows is YOUR ignorance.