The World Relays is an IAAF series event, therefore I doubt NOP/OTC will totally ignore it simply becasue it will probably factor into world rankings and DL points. Being that there are no global championships this year, world rakings will probably be a major performance points incentive. Prefontaine is the following week and that could factor into the decision for some athlete or perhaps 5k/10k athlete like Rupp, a 1500 could be tune up.
Btw, the fact that you are not hearing much from USATF has more to do with having to pick between athletes than not getting enough commitments. From what I recall from last year, most of our elite were very excited about this event. Also, the 4x8 and 4x1500 WR and at least the AR will come out of his meet and who would not want to be a part of that.