Using the actual math, he's still not a sub 100 point player like is being claimed by others.
Projected to 82 games is 1314 5v5, that's 72 points at 3.28p/60. Add the 12 in 100 of ES time, and 54 of PP, you get to 138 points. It's not 165, but the 12 and 54 are at 70 games, not 82, so he's definitely over 140.
Going the other way, 1314 5v5 at 2.00p/60 is 44, rounds out to 110. Naturally this includes McDavid still on the powerplay, so if you substitute McDavid out of the roster he won't get as much PP points, but also I don't think he would be sitting at 2.00p/60 if you gave him a true winger like MM to play with.
His true range is likely somewhere around 100-115 points possibly dipping under 100 in a down year, but I'm not sure how that brings us to conclusion he could possibly struggle to break 85 points as you claimed. It's a logical fallacy to me that people keep saying "if you put him on a worse PP team", when part of the reasons those teams are going 20% and sucking on the PP is that they don't have Draisaitl on it. I'm not saying Draisaitl is solely responsible for us being top 5 in the league all-time right now, but its massively hypocritical to adjust his 5v5 points down with no McDavid but then try to use current bad PP% on other teams to project his PP points over there. They would decrease away from McDavid, but there is no evidence to suggest ANA PP stays as bad with him on it.