It took 7 seasons before he had a supporting cast good enough to make a deep playoff run, but even before that time he'd become obviously elite. He even had his highest scoring season before the likes of Larry Murphy, Ron Francis, Jaromir Jagr, Kevin Stevens, Mark Recchi, et al were on the team, though of course by the time they were there Lemieux was missing oodles of games pretty much every season. If he hadn't.....
I'm not sure Lemieux's scoring totals would have been any better with or without some of those guys. Obviously, he was better off with
some elite players to play with, but stockpiling good players doesn't often result in the best guy having career numbers.
Actually, with the exception of 1992-93 (which was an unusually high-scoring season for elite players, and with Mario's totals boosted by the Pens finishing with that 17-game win streak), Lemieux's per-game scoring paces weren't any better in 1989-90, 1990-91 (barely played), 1991-92, 1993-94 (barely played), 1995-96, or 1996-97 than they were in 1988-89 when Rob Brown was his line-mate.
Gretzky is a bit similar, in that he had his 92-goal season really before the rest of his teammates had caught up to full speed yet. And the Oilers often say the 1986-87 team was the most talented team they ever had, but Gretzky had his lowest point total in six years.
The thing with having a lot of good players on one team is that they all have to play and they need ice-time.
But a lot of good players is good for winning championships...