Why cant carbon fourteen be used to date a dinosaur fossil that is 1 million years old?

Carbon-14 has a half life of about 5,730 years, meaning that it can only date back to thousands of years old. also, the amount of carbon in the earth's atmosphere has been increasing since the beginning of time, so carbon dating is not a very good way to date fossils. Carbon dating only works on things that were once living.
Scientists have determined that it would take 30,000 years for the carbon to reach equilibrium, and that the earth is less than 1/3 to equilibrium, so it follows that the earth is less than 10,000 years old.