Honestly, he isn't. Other than his severely inflated totals due to when he played, I am not sure how this misconception exists. But the Gartner over-rating these days is def weird. He had a long, very consistent career and huge kudos to him on that. But he also had the good fortune of playing in a very watered down league, with terrible goalies, in one of the easiest eras ever to score goals. The reality is, though, he wasn't even one of the best goal scorers among his own peers during his career, let alone all time. During his career, 20-30 guys a year were scoring over 40 goals and Gartner only once cracked the top 5, and he reached 5th. There were seasons where he scored 40 goals and wasn't even in the top 15...
- 1979-80 he nets 36, 28th overall. 9 guys over 50, 24 over 40
- 1980-81 he nets 48, 10th overall. 9 guys over 50, 19 over 40
- 1981-82 he nets 35, 40th overall. 10 guys over 50, 22 over 40
- 1982-83 he nets 38, 24th overall. 7 guys over 50, 23 over 40
- 1983-84 he nets 40, 21st overall. 8 guys over 50, 24 over 40
- 1984-85 he nets 50, 9th overall. 9 guys over 50, 23 over 40
- 1985-86 he nets 35, 34th overall. 6 guys over 50, 23 over 40
- 1986-87 he nets 41, 11th overall. 5 guys over 50, 17 over 40
- 1987-88 he nets 48, 10th overall. 8 guys over 50, 29 over 40
- 1988-89 he nets 33, 36th overall. 6 guys over 50, 22 over 40
- 1989-90 he nets 45, 9th overall. 8 guys over 50, 21 over 40
- 1990-91 he nets 49, 5th overall. 4 guys over 50, 20 over 40
- 1991-92 he nets 40, 14th overall. 5 guys over 50, 17 over 40
- 1992-93 he nets 45, 19th overall. 14 guys over 50, 25 over 40
- 1993-94 he nets 34, 35th overall. 9 guys over 50, 23 over 40
- 1994-95 shortened season, he's 85th overall
- 1995-96 he nets 35, 28th overall. 7 guys over 50, 18 over 40
- 1996-97 he nets 32, 44th overall. 4 guys over 50, 12 over 40
Throwing out his last season cuz he fell off, as players do, his average seasonal placement was 26th and he was 20th in GPG among his peers. Sure, in GPG during his career he lost to guys like Gretzky, Lemieux, Bossy, Dionne, Robitaille and Hull. But during his career, he was also behind Kerr, Nieuwendyk, Simmer, Bondra, Goulet, and Vaive in GPG. He had great length of career, and he deserves huge credit for playing at a high level for so long. But when your GPG during your career are, in that time period, behind Petr Bondra, Charlie Simmer and Rick Vaive, you are not close to one of the all-time great goal scorers.
The above is why, despite potting over 700 career goals, Gartner is basically almost never considered among the top 100 players all-time. If you don't think Garnter's era affected his all-time placement and his 0.49 GPG aren't severely inflated, consider that Pierre Larouche and Blaine Stoughton played about the same time as Gartner and that they also have a career 0.49 GPG. That should pretty much say it all right there.