I'm just going with my own definition of best player ever and not evaluating how competitive, driven etc. that they were or were not. How can I measure the competitiveness of a player, especially ones I never saw play.
Just on numbers alone I am going with Wilt. This is a guy who is generally considered the best athlete to ever play pro basketball. If you didnt know that read a little on him or watch on you tube. His vertical was higher then MJ's, his strength greater then Shaq's and not just by a little either, and even though he played on teams that were not considered nearly as talented as the Celtics he managed to take them in four series to the deciding game and lost all four by a total of 9 points.
You can argue that yes his teams lost and Russel's teams won but do you think Russ was the go to guy down the stretch for his teams? Had Chamberlain had more help he would most certainly have more titles. There was a stretch of about 8 or 10 games on season where he averaged close to 70 a game!