This.
I lived in Tahoe for 6 years, and skied Squaw every day.  There were definitely more skiers at Squaw and Alpine.  Furthermore, skiers were dominating the big lines at Squaw.  That is not to say boarders did not throw down, because they did, but the Palisades would be at least 75% skiers on a big day.
Now I ski Mammoth 3 weekends a month, and Mt. Baldy on the weekends I don't hit Mammoth.  I would say Mammoth is about even, definitely a bigger boarder presence than Squaw.  There are lots of skiers there too though, anyone who says boarders dominate Mammoth does not know what they are talking about.  My ski lease has 6 people this winter, and all of them are skiers.
Mt. Baldy is a cool little mountain in socal.  It has terrain that is much better than bear/summit.  You would not believe it is in socal.  It is mostly skiers.  Bear/Summit/Mt. High are about 75% boarders, or more.