The Flintstones are a post apocalyptic family living sometime in the future after Jurassic Park brought back the dinosaurs. That's why they are a few thousand years old and not millions of years old.
Even we
know that
dinosaurs are
a few thousand
years old! Hey Fred,
I'm hungry! Lets
go out for some
brontosaurus.
steaks! Hey, I'm
a dinosaur! Yea! Bam-Bam! Angel Soto