Dinosaurs are extinct, no argument. Where disagreement begins is what caused dinosaurs to check out.
Scientists weighed-in by delving into the provable with a matter-of-fact methodology that advanced a single plausible cause:
A rogue asteroid strayed off-course and collided with Earth, creating violent shock-waves that reduced all living matter to pink and green mist.
Conspiracy theorists never miss an opportunity to thrive on the dark side. They offered hundreds of sinister scenarios, but ultimately consolidated to promote one: Dinosaurs were the first victims of population control. Government "cooked the books" by intentionally designing census forms with no categories for dinosaurs, and census-takers were unable to include the beasts in the count. Cartoonists suited up in greater, yet wackier numbers, and dived into the improbable with a what-the-hey lunacy having its own impenetrable logic: Gary “Far Side” Larson theorized dinosaurs became extinct because they failed to heed the surgeon general’s warnings about the dangers of smoking cigarettes. Dan “Bizarro” Piraro believed dinosaurs missed boarding Noah’s Ark by an hour because they forgot to adjust their watches for daylight savings time.
My theory is Anti-freeze was not yet invented, so dinosaurs were ill-prepared to ride out sub-zero termperatures and marauding glaciers.
Science, conspiracy or cartoons, it all works. So no matter how you look at it, pink mist or a puff of smoke, just like that - Poof! - Dino the dinosaur was gone!