There were many great big men back in the 60's and 70's that would compare favorably with those you mention, starting with Russell, probably the greatest defender of all time, but including guys like Willis Reed, Walt Bellamy, Nate Thurmond, Elvin Hayes, Artis Gillmore, Dave Cowens, and Jabbar. Your argument has been made frequently by those who are not that familiar with both eras.

There is NO comparison between a Dwight Howard or Tim Duncan and Wilt.