Not all skaters who can receive international assignments do. USFS often doesn't send skaters to all competitions.
I don't understand why Caroline Zhang got assigned repeatedly to Skate America. Lysacek sells tickets, and he's the reigning Olympic champion who has been training seriously this season (and possibly the last), so his assignments are understandable. I don't think that because bad or misguided decisions were made in the past means that bad or misguided decisions should be made now.