Who comes up with this nonsense? I'm assuming you realize it's the same stadium, but both were sold out. That has to do with how they set up the stadium for each event. They had 77k+ there for last year's football college championship.
+1
Superbowl attendance numbers are dictated by supply, not demand.
Just look at (approximate) avg. selling prices from this year:
MLS Final - $293
Superbowl - $4,000+
Also, the MLS Final is played in the home team's city...