With "Improvements, fixes and/or changes made to the game, are to be expected." devs can actually remove (let's say) half of the cars available now and add them to S3 in further versions and deny connection to older versions to master server,making impossible to drive these cars online without upgrading licence,and you could not protest a thing,because it's a change,that was to expect!
On other hand - would you go to McDonalds to ask for cheese when they add it to their randomburger,when you bought it yesterday without it,because it wasn't planned to put in it yet?
Anyway - when you bought S2 licence,you got all the content available then,there are no promises that you will deffinitely receive more content. If you feel somehow cheated,it's deffinitely your hopes that make you feel that way!