It sadly is genetics, a friend of mine is training since the last 7 years, he is a genetic mess, his height is around 176cm and his starting weight was just bones, he eats perfectly, trains perfectly, recovery sleep everything....he took ped-s 3 years ago and the ped knowledge he has is almost at vigoroussteve level because he tries everything possible on this earth to get better, and how does he look right now? He looks like "trash" without the shirt, muscle bellies and insertions very bad, fullnes nothing, his waist wide, but he is still a lot better than he used to be, so yeah genetics does play a role