I think the payments in GT7 map races are quite skewed favoring Le Mans WTC700 and Sardegna WTC800 races, because they are almost impossible not to get a clean race bonus in (clean race = 50% higher event payment). But yet many other races like WTC800 Watkins Glen, Spa WTC800 and Tokyo WTC600 are the complete opposite difficulty in getting clean race bonus. I think it goes for many other races, they would pay much more if you got the clean race bonus easily. I think this may be the reason why event payouts are so unbalanced paying.
So what we really need is a balanced clean race bonus system for all races. Should be fair, and not too easy either. Like in sport mode there it works imo. Like I have won the Le Mans WTC700 race with a clean race bonus, despite crashing into AI, spinning and hitting the wall, shortcut penalty, all in same race 😅