How can you not win the Hart while scoring 199 points while being a part of 57.3% of your teams goals. Which is an NHL RECORD. He set the record for what the Hart is supposed to be about.
If points % determined the Hart, Gretzky wins the 1997-98 Hart Trophy. In fact, since 88-89 Gretzky scored on 9 of his team's 11 goals against Calgary, he should get the Smythe.
Then again I don't value points% as much as you. It just seems to reward top players who happen to have bad second and third lines. When they were on the ice Gretzky had a point on 78.9% of his team's goals and Lemieux had a point on 78.3% of his team's goals. Neither appears much more valuable to their team's top unit when they are on the ice. In fact, Lemieux's linemates narrowly outperformed Gretzky's.
Gretzky was the most visible reason for the Kings going from 18th out of 21 to 3rd out of 21, the Kings faced a clearly harder schedule (going by SOS on HR and being in the Smythe in general), and Wayne still put up 168 points despite seeing around 100 fewer powerplays than Lemieux did. At even strength Lemieux outscored Gretzky, but the margin was 102-100.
Both guys were on the PP a lot. Lemieux was on-ice for 92.44% of his team's PPG, Gretzky for 87.80%. As a share of their PPGF totals, Gretzky scored on 73.6% and Lemieux scored on 71.8% of PPG they were on-ice for.
Giving Gretzky the 1989 Hart made sense. It certainly made more sense than giving Mario the 1986 Pearson, where Gretzky outscored Lemieux by 74 points despite the Oilers receiving a league-low 295 PPO to the Pens league-high 425, and Gretzky succeeding in the more difficult task of getting points on >50% of a good team's goals.