That’s the majority of human migration. We follow water bodies, but not to the exclusion of all growth. By that logic we’d never have made it inland at all.

There’s no logical reason for a supposed pre Clovis culture to not go inland. 10,000 years and you really think they stayed 10km from the waves that whole time? It makes no sense. They would be the only group in human history to do that and they’d have needed to do it for millenia