I hate to correct you BUT: XBox allows you to set up a family profile account to be able to share DLC content between people in the same household.
I have 4 people who use my PS3 and play most of the games I buy. Myself, my girlfriend and her two early teenage kids. So what you are saying is it is ok for me to buy a game for $60 that has over 20 tracks and over 1000 cars and over 1000 paint colors.... for $60 that all 4 of us can use.
But if I want DLC content for all 4 of us to use I have to pay $48 for 1 Track (cause a cart track is worthless for online play), 15 cars that are for the most part just remakes of existing cars and not anything new (IE Koeningsegg CCX, Ferrari FXX, Gumpert Apollo Race, Ultima GTR, Ariel Atom, and about 30 other GREAT cars I could name off the top of my head), a few paint chips that I can only use ONCE as in ON ONE CAR IN MY GARAGE OF OVER 800.... That is just crap.
EVERYONE EMAIL SONY PLAYSTATION CONSUMER SERVICE AND COMPLAIN
http://us.playstation.com/support/ask/