Events like this are put out for bids. What other places bid for it? What was going to be the cost of hosting it there? Having worked enough, a place could be appealing and then you run into the costs and it gets crazy. For instance, NYC...union labor costs and BS stuff drives up the cost. Want an extension cord? You cannot plug one in and run it, gotta have an electrician come do it. Oh and you will get charged for that and it will take a day to get it done. There is a lot that goes into an event.
From one perspective Eugene makes perfect sense this year since it is the location for Worlds. Getting used to the facility is a good thing.
People talk about putting it in NYC. That is great for folks close by and maybe you could fill the stands with just them in which case that goal is met. But the travel cost then shifts. (Travel costs are going to be an issue for someone).
Eugene and the area has passionate track fans I am sure, but sort of like what people say about hockey: every city as 20,000 rabid hockey fans, but that is (was) the only people who would come out. (Hockey has gotten a lot more popular so less of an issue now). No doubt a lot of people are choosing what events to go to. Maybe a lot of folks who would come in are waiting until Worlds.