Oates was also stuck behind Yzerman for years, while Selanne was given first-line ice minutes from day one because he played on weak teams.
In 1991, Oates finished 3rd in scoring while missing 19 games. I can't envision selanne outpointing guys like recci, sakic and yzerman while missing 1/4th of the season.
I don't think either of us is saying Oates is equal player to Sakic and Yzerman, but that's impressive season for sure. I have about equal example though. While I think Selanne's 97-98 season is his most impressive, even including the 92-93, Ducks weren't a very good team the year after either.
Selanne was 2nd in points in 98-99 season, outscoring Sakic and Forsberg (who had healthy season) in fewer games. Calculating if he had missed 19 games he would have been at 90 points pace, good for 9th place, 11 points shy of teammate Kariya who was 3rd and 7 points to Forberg (who was 3rd).
Now thats not equal to Oates in 91 itself, but while Kariya and Selanne had a superb chemistry, I am fairly sure Hull's 86 goals that year helped Oates's point totals a bit more (although Oates helped Hull's undoubtedly as much).
Apart from Kariya I don't think Selanne had nearly as much help that year. For example having someone of Scott Stevens's calibre, like Hull and Oates did, in the backlines, would probably have helped their powerplay a bit though.
But no doubt that is quite a season for Oates and an excellent example of how he managed to improve the goal totals of Hull and other players, such as later he did with Juneau.