But we don't have any evidence for anything approaching civilisation, fair enough humans have been industrialised for 200 years, but they've been building to that point for 10s of 1000s of years.
If there was a stone age dinosaur civilization that lasted for 10,000 years, what evidence of it would survive? We only even have one fossil of a dinosaur per 10,000 years of dinosaur history. They key idea is how sparse our fossil record is compared to the vastness of life's history. Plus we are talking about 100,000,000 years ago - the chance a flint or metal tool, or a stone building would survive that long and be found by us is zero or close to it.
It's also not far fetched. The only "remains" of the dinosaurs era are birds. These are smart animals that actually build their homes. It's possible that dinosaurs had and built homes and maybe had a small civilization.