Since Ovechkin and Crosby entered the league, the term "generational" has been en vogue. Consider that, prior to those two, there have been 4 players considered generational over the last 100 years: Howe, Orr, Gretzky, Lemieux. That's it.
Suddenly, Ovechkin and Sid enter the league and we've more than doubled the amount of "generational" players: Ovechkin, Crosby, Malkin, McDavid, Matthews, Dahlin.
4 over the course of history, then suddenly 6 more since 2005. Next Hughes will be, followed by Lafrenierre.
Personally, I think there has only been ONE generational defenseman ever, and that's Orr. Bourque, Potvin, Lidstrom, Harvey, etc. are not generational in my eyes, although they are elite, megastars.