I see no evidence to justify your vain imagination and belief, either.
Try to run some numbers in logistics before imagining more than 100,000 ever lived in the Americas prior to 1491.
Of course, those who pretend to be well studied on the subject positing millions of inhabitants also don’t mind overthrowing all other scientific datum prior to their generation, simply to advocate their beliefs.
It’s absurd to suggest otherwise, unless one is attempting to overthrow all American governments by suggestion that ‘native’ populations have a more primal right to governance than legitimate authority already possesses.
IMHO, the entire movement is an attempt to counterfeit history to justify modern social restructuring of national governance.