That’s exactly it. Cars that you can only obtain for a limited time either by playing 1P events that only exist for a limited time, or by grinding out specific MP events that only exist for a limited time. Next month, more FOMO, lather, rinse, repeat.
I suppose there is some fun to be had with monthly Rivals events or hotlapping competitions, if you’re into that sort of thing. If you can find a league, that can bring some fun and help you overlook some of the game’s shortcomings (for a while, anyway).
There are a few more tracks now than there were at launch, but the majority of the updates, to me anyway, have kinda just felt like shifting around deck chairs on the Titanic.