Ovechkin's 63-goal season is considered one of the most impressive seasons for goalscoring, ever.
And really, it depends what you mean by magnitude. because even when Moore set a points record, Hart voters considered him the 5th-most valuable player in the NHL. Which is quite curious. And probably more important than just looking at raw goal or point totals, as I'm sure you'd be first to admit.
Remember, Ovechkin has 100 years of history to beat when it comes to seasonal records, Moore had 40-50 years to top. There should be little doubt that Ovechkin is already better than Moore ever was. The only question is, after five seasons, has he provided more career value than Moore did, when Moore's "merely good" seasons and playoffs are considered?
It works both ways, bud. Smaller league = higher percentage of HHOFers to play against = higher percentage of HHOFers to play with. And as a Hab, I'm pretty sure this benefitted Moore more than if he played on another team.
His career doesn't necessarily have to be finished, or ten years long. At some point, whether his career is over or not, there will be a time where we can all agree, "ok, Ovechkin has now done more than Moore." I don't know that we're there yet, but apparently, most people think we are.