No — it's just paid for in different ways (ie. taxes).
I enjoy playing all three. Yes, GT on a strict by-the-numbers basis, Sport has less content than either in terms of cars and tracks. But games are more than those two numbers.
I've said it since release; if PD starts up paid-for DLC, and it's all genuinely new content (or at least almost-all; ie. not stuff we've largely seen from GT6), I'd gladly hand over money. I've done so with the other two titles. I think showing appreciation for a team's hard work via a few extra dollars is hardly unreasonable.