Good point...and thank you for correcting me 👍. I am, admittedly, half asleep today so clearly misread/misinterpreted/need an eyesight test.
Now that I understand it properly, I'm not sure "game design based on the premise...." is valid as GT5 required grinding and, from what I understand, had the same level of payouts in the seasonals to begin with (no idea when the repeatable races started...and didn't I read somewhere that GT5 didn't even have the seasonals to begin with?) yet did not have MTs in it. The game design seems to be the same as before, just with the added MTs. And I remember grinding certain events in GT4 to get the high value vehicles (a certain rally car for 365k credits springs to mind).
However, knowing where GT5 ended up with the high-paying repeatables etc, then starting GT6 with no repeatables (and only a few bonus high paying), I would agree that the game design for GT6 may have been structured for MTs...otherwise they would have surely started repeatable seasonals already, not to mention their changes in prize money/car prices so soon after release. I guess that shows that you can look at it either way