Definitely an interesting question. Here are the theories so far:
1: New doping tests have top athletes scared of getting caught.
2: Relaxed performance clauses in sponsorship contracts.
3: All three Americans focused on events outside their specialty this year.
4: Protest against USTAF.
5: Feud between Bobby Kersee and USATF?
6: Stress over the Olympics-Worlds-Worlds-Olympics-Worlds sequence.
7: Mental Softness is the new normal: Thank you Simone Biles, Osaka, Luck, etc.
8: Just a coincidence.
Personally, I'm reevaluating whether maybe I should just root for the athletes that clearly love the sport, rather than the athletes with USA on their uniform: Warholm, Bol, Kerley, Ingebrigtsen, Hodgkinson, Kipyegon, etc.
