Does anyone know the major difference between building teams today and back in the 1960s? There are scouts. The college game was on a regional level. Everyone on the West Coast had heard of Bill Russell, but about a year before the draft Red Auerbach had never even heard of him. Red never even saw Russell play, but because Red had friends the coached college around the nation he knew about players such as Sam Jones or Russell from his coaching buddies. So in a way the Celtics had an advantage over every team in the NBA when it came to drafting talent.
When Wilt played with the Warriors those first few years, the second best player on the team was an old, past his prime Paul Arizan and the third best was a young Guy Rogers. By that time Russell's Celtics had several players already built around him. The Cousy/Sharman back court was just using up it's last few years of being good and players like Tom Heinshon, Frank Ramsey and Sam Jones were all in their mid 20s.
Fastforward to when Wilt played with the San Francisco Warriors, Wilt had the rookie Nate Thurmond, and Guy Rogers as his best players while Russell had Havlicek, both Jones', a still in his prime Tom Heinsohn and some other nice bigmen.
It's also a common misconception that Russell shut Wilt down. Nope. Russell would even tell you today that Wilt scored on him just as easily as he scored on anyone else. The Celtics would always triple team Wilt, and back then it was almost litterally no blood no foul so Wilt would come out of games beaten up all the time.
Very few people here know anything about the era of basketball before the ABA/NBA merger. Since there are few films of games back then, do yourself a favor and pick up a book.