Very different scenarios.
The difference between Crosby and McDavid's on-ice ability is largely marginal and the difference in hardware mostly comes down to health. Last year is the only full season in McDavid's career that is clearly better than anything from Sid, even when you account for scoring differences. But the way people talk about McDavid's offense, you'd think he was in the midst of a Gretzky-like prime putting up these totals year-over-year. He's not (or, at least, there's no way of knowing this until he keeps it up for another 6-7 years) and just about lost out on the previous year's scoring race to Gaudreau and Huberdeau.
When there isn't much separating two players (as was also the case in the Sid vs. OV debate), the little things matter. The problem was that Toews was nowhere near Crosby's level and it became a running joke that the hockey hipsters of the late 00s/early-10s would use defense to make up for a massive difference in offensive ability.
