If you want someone that was great in prehistoric times you go with Bradman. His average speaks for itself. If you want the outright best player in the game you have to take Tendulkar. Viv might have been great but in the 50s it's about as relevant as Bradmans era but without his statistical feat.
Dude what.
1. Richards didn't play in the 50s. He played in the 70s and 80s.
2. Tendulkar isn't the 'outright best player in the game'. He certainly had amazing longevity, but it's pretty easy to argue he wasn't even the best player in his generation. Kallis, Ponting and Lara match him in terms of ability as a batsman, although as I said, Tendulkar beats them in longevity.
3. Bradman is so much better than all of them it's not even worth talking about. Bradman averaged almost twice as much as Tendulkar. He's the GOAT. I can't even believe people try and argue it. If there's one sport in the world where there's an undisputed GOAT, the answer is cricket and that person is Bradman. No arguments.