For those of us who own the game (since October 2011) is not a problem but for the ones that have no idea why this is happening is all because of the licences (they are trying to get them but is not as easy to get them in time, they have to sign contracts and need to approve a lot of content, etc) and of course the game needs some more polishing in some areas.
I like the game more and more with each build (and we get new ones each day), I can assure that it will be fun to play and great to race with it.
Be patient.