Let us be realistic here; if Hashirama got the same unfair boost that Naruto, Sasuke, Obito, Kaguya, Hagoromo, got (and I could go on and on), he would destroy everyone. He already does and he's never gotten any kind of power boost coming from anybody at all (unlike EVERY single other top 10 character in Naruto). All of those children without any of the boost they got would be crap. Hashirama would literally molest them if they didn't have "the Sage's power" within them (and ironically, the Sage's power is also a boost that he got from the 10 Tails and his mother whom ate the fruit to get yet another unfair boost).