Originally Answered: What if men of recent years literally made the "artifacts" they said were from hundreds/thousands/millions of years ago?
Based on science past record, you should be able to cash in on it and die long before anybody figures out it is a hoax. Look at the Piltdown Man. Presented in 1908, not exposed as a fraud until 1953.. This lead people to look closer at Dawsons work and they found no less than 38 fakes and hoaxes. Dawson apparently made a career out of duping scientists starting as early as 1891 with his discovery of a bird mammal transitional form Plagiaulax dawsoni.
That was a deliberate fraud, but what about the noseless lemur... Discovered in 1898, Arrhinolemur scalabrinii was referred to as the Noseless Lemur. After 114 years later, Brian Sidlauskas a fisheries expert and Richard Vari, an ichthyologist did a detailed examination of this 8 million year old primate fossil and determined it was not a Lemur, it was a fish.
There are other examples but the pattern is be it honest misinterpretation of the artifact/fossil or deliberate fraud, if it is in agreement with current thinking paleontology is sufficiently subjective that one can successfully pass something off without facing much critical scrutiny, and that is all you need. Just a few finds to make yourself a name and you can collect speakers fees for guest lectures or presentations for the rest of your life. you may even get other bankable honors - honorary degrees, and other things that allow you to raise your fees for speaking or get your foot into to door to more lucrative venues. That is not to say you could cash in writing books, peer review fees, appointment to review boards with a scientific journal or other such things that tend to be reserved for people who make such discoveries.