I think the absurdity of Hassan's London win has warped our brains a little bit because it felt impossible, so now the impossible feels possible. London was insane. Instant classic and one of the best races of all time. But that's not the same as being one of the best runs of all time.
Hassan is the GOAT, and her insane ability allowed her to win a race she really shouldn't have won. But let's be clear-eyed for a moment. 2:18 is not that fast these days and the second half was really pedestrian, despite conditions that were good enough for Kiptum to tear things up on the men's side. I tend to assume that when the top runners run relatively slowly that it's due to conditions/tactics/etc. rather than just everyone suddenly running poorly. But I think it's safe to say that in a performance sense alone, the race that Hassan ran to win doesn't stand out as being particularly strong (considering the rarified air of the major marathons). Could she win the Olympic marathon? Absolutely. But she's not some heavy favorite who can run races all week and still be expected to win.
Also, stopping and stretching multiple times and still coming back to win is unbelievable. I'm not sure anyone else in the world could have done it. But there's a worrying side to it, no? What if next time, the tightness is little bit worse and she has to drop out? Some runners have problems during a marathon more frequently than others, and the fact that Hassan came back to win doesn't mean it's not a potential issue for her.
So all that said, of course she can't win (or place highly in) FOUR different events in Paris. I think that's kind of obvious. It would be a legitimately tiring week for even a top MALE runner to do that (in the women's races). I think we underestimate her 2019 performance, which is totally unparalleled in the history of the sport, and may be the greatest single-meet performance in history, at least on the women's side. To expect Hassan to replicate that is insane (although I'm excited to dream about it!). To expect any sort of improvement is nigh on impossible.