The car count I understand because it comes after GT5/GT6 but...I don't get the complaint about the car count. GT3 launched with almost similar car count, didn't hear anyone complain back then.
How people says it has way less offline content than previous games is ridiculous to be fair... of that it is missing single-player content... the only thing missing to be fair is the B-Spec mode which not all GTs had.
GT League did has less events than GT5/GT6 but it has more Challenge/Mission.
It is a close call to say which one has more offline content without go menu to menu counting because GTS is pretty rich in offline content.
I can even say it has better single-player content than previous GTs.