Zhou finished sixth at the Olympics. That was a huge deal for him, and considering that he won a World medal the very next year, I don't see how you could argue that sending him to the Olympics didn't pay off for the USFS.
Sixth at Olympics doesn't mean anything (and Ross had the ability to finish there too). I'm sure he was happy to go and be at the Olympics, but it didn't get any extra coverage, and it doesn't give USA any additional points or anything. Ross beat him at the most important competition and had the seniority and his programs were more likely to spark viewer interest, which leads to more media coverage and more people wanting to get into figure skating (either as viewer or spectator).
Vincent could have won a Silver at 2018 Worlds AND his Bronze at 2019 Worlds. Being introduced as a World Silver medalist is more impressive than "6th place at Olympics". It's possible to say he could have won Silver at Worlds anyway and he simply messed up, but I think he would have been hungrier to prove himself and put everything into Worlds, if he hadn't gone to the Olympics. The same as Wakaba Higuchi skating her best LP ever there, after missing the Olympics.