Yeah, I agree. I've played this game since launch, and I've only streetpassed like three times. I've taken my 3Ds so many places, but apparently I'm the only person who has one. I wish I could go to Japan. I've heard Streetpass is super easy to get over there.
If you have a second copy and a second ds , you can get spotpass from yourself. Though it's fun and surprising to get it from random people. I seldom get any though.
I never get streetpasses, even on the airport I got none.