We throw around "era" way, way too much on these boards.
Both of their (somewhat flukey) career seaons were in the same year and they had 13 overlapping years in their careers.
How much are we going to discount Robitaille? even if you take away 10 goals each of those seasons before hand, he is still a 500+ goal scoring LW and it is still comparable.
I mean I agree Selanne is better and I voted for him but come on..
Selanne's 92-93 wasn't even his best year. He was better during the dead puck era with Anaheim, while scoring fewer points, because it was just that much harder to score. Selanne was an Art Ross runner up twice in the late 90s. One of those years, he was a Hart finalist. Robitaille was never close to that level.
Scoring dropped like a rock after 92-93. That season, 7.25 goals were scored per game. In 96-97, it was at 5.83. In 98-99, it was 5.27. This is an enormous difference in just a few years.
He's a nifty graph illustrating this:
http://www.dropyourgloves.com/Stat/LeagueGoals.aspx
Back to the topic, here are their top 10 points finishes and goals finishes:
Selanne points: 2nd, 2nd, 5th, 5th, 7th, 8th
Selanne goals: 1st, 1st, 1st, 2nd, 3rd, 10th
Robitaille points: 5th, 5th, 9th, 10th
Robitaille goals: 4th, 4th, 6th, 7th, 7th, 9th, 9th, 10th, 10th
It really isn't that close. Robitaille had more injury-free seasons in his prime, which he deserves credit for, but the gap in peak performance is quite large.
The reason why historically LW is a weaker scoring position than RW is exactly what you say. Scoring wingers have been encouraged to be on the right side partly because of many centers being LH shots as you say.
That also means that there is a slight bias to scoring on the right side because obviously that is a forehand pass option.
So yes.. it is relevant.
I guess it could be relevant in a close case, but I don't think this one is close.