Why is it Kevin Garnett put up bigger numbers, and more talented but Duncan is all time best at Power Forward?

Isn't this contradictory? Years from now, we'll pretty much as a whole will agree Tim Duncan is the best Power Forward of all time. Kevin Garnett and Tim Duncan were in the same era and only 2 years away from one another entering the league as rookies. Kevin Garnett put up the better numbers and career totals to show that. Tim Duncan has more rings of course, and well now that Garnett has 1. This could be the year that Garnett faces Duncan in the Finals. These were my two favorite big men since they came in the league. Never could I decide which I liked better. This is going to be looked back in time as the "Bill Russell" vs "Wilt Chamberlain" or in the later years..."Lew Alcindor(Kareem Abdul-Jabbar) vs "Wilt Chamberlain" rivalries all over again. Being that you see it right now, who will you think you will be saying 20 years from now who was better between Duncan and Garnett as the greatest power forward of all time between the two of them?