Point totals really depend so much on factors that are outside of a player's control. What can be said is that Draisaitl is a world class offensive player on his own. He's the modern day hybrid of Jagr and Thornton.
Obviously playing with McDavid helps, but I think McDavid benefits from Draisaitl a ton as well, especially on the PP. They have perfectly contrasting styles, but I think Draisaitl's patient, deliberate style (combined with his deadly low circle one timer) is a huge part of what makes McDavid so difficult to defend shorthanded.
Still, it can't be denied that at 5v5, Draisaitl's production drops from "superstar" to "low end first line center".
Last 3 years at 5v5
Draisaitl w/McDavid
3.28 p/60 (60p in 1095 mins)
Draisaitl w/McDavid
2.00 p/60 (74p in 2221 mins)
It should be noted that he doesn't always have the best linemates without McDavid, but still that's a precipitous drop.
2.00 p/60 is equivalent to roughly ~43 5v5 points in an 82 game for a guy with his generous 16 mins of 5v5 time a game.
So if he were on a team without a great PP or extra help at 5v5, it's quite possible Draisaitl would fall well short of the 100 point plateau, and may even struggle to break 85 points.
