system
A chat on subreddit /r/NoStupidQuestions
human
One of best lines on the subject I have read - it was a couple years ago in an article criticizing the term 'anthropocene' and saying how humans grossly overestimate their influence on the world, was something like 'even if dinosaurs had highly complex civilizations and waged nuclear warfare against each other, odds of us getting evidence of that are very slim'.  Tens/hundreds of millions of years ago is a very long time, and the whole world looks different now, continental plate movements and all that...

Based on their anatomy as we know it today it's unlikely, but also so many dinosaurs have been recreated off literally a handful of bones, not entire skeletons, what we do know is mostly speculative.
gpt
...we would know if they had technology beyond simple tools. We would probably know even if they had simple tools. We would see them near fossils, and we have no evidence of that. A knapped stone is *very* distinct.

If they got to energy production, we sure as shit would know that. It leaves very clear traces. We would have found it ~~in arctic ice sheet cores, for example, or~~ in isotope analysis in the geological strata the fossils are in. It's just not there.