There's a flaw in your formula there...
You're counting games that Lemieux played up until he was 40 years old, yet only counting Gretzky's GPG up until what... 30 or so?
Lemieux in his first 788 games (through his age 35 season) averaged .82 GPG
Gretzky in his first 774 games (through his age 28 season) averaged .82 GPG
Now take a look at the league's yearly SV%...
http://www.hockey-reference.com/leagues/stats.html
When Gretzky was setting the goal scoring standard the league's SV% was around .870 - .875%
When Lemieux scored 69 goals in 70 games the league's SV% was .898%
When a 35 year old Lemieux lead the NHL in GPG the league's SV% was .903%
And yet despite the statistics there are still some who say...