I think even with 1 cup, he'd be ahead. They're still in the same tier to me. McDavid is a better scorer even when adjusting for scoring environments. Even so, he--like Crosby--has years where others surpass him in terms of scoring. Art Rosses have gone to Drai, Kucherov, and Mack has kept pace too... It's not like Wayne and Mario from the 80s to the early 90s where they only lost to each other.
He's better than the aforementioned guys--being a tier above them due to consistency--much like Crosby who was better than Malkin and Ovechkin over the years. I feel McDavid has separated himself more from the his versions than Crosby did, but not by enough that he'd be in the Lemieux and Gretzky tier. He and Crosby are in the Jagr tier in terms of separation.
We *are* in a higher scoring era, given that we only had a couple 100-point scorers at most a season for most of the 2010s. Suddenly, we have a handful again. That can't all be a coincidence, especially since Kuch, Mack, and McDavid played at the tail end of the lower scoring era too.