By "overdone" do you mean just more than what it will settle down to? Because although the statewide totals sound big - as would the comparable figures for alcoholic beverages - I don't know that it amounts to all that large a proportion of the population using all that much pot per person. Particularly when compared to the same numbers pre-legalization.
Yep. Some things are adopted slowly. Others, especially when previously suppressed, may experience a transient burst of popularity before dying down to a steady state level.