The ATC offers the fan a team from their city to root for. They will begin to care about the individuals of the track world once they have done something for their city. Now you don't have to be the 5 people in the USATF that are the most popular to get your brand out there. The smaller time athletes will be able to network with the bigger athletes and showcase their talents for 5-6 weeks in the spring to coaches or sponsors. And since you are competing for a locality, smaller sponsors will want to but their brand on the athlete to market intra-city.
For the elite athlete, this league will not be a hindrance to their season, it will be a 6 week training camp. For example, Christian Taylor is selected by the Atlanta Track Club to compete in the Triple Jump and run the 4x400m. He will only have to do 4 jumps and 2 races, for 6 weeks in a row. The performances are less important, it is more about points, so only when he has stiff competition does he risk high octane performance from his body. He will train in Atlanta during this time and build networking and camaraderie amongst fellow athletes. Track already has a great reputation for this, it would only expand it. Taylor would also feel a sense of purpose during these meets instead of a very personal and unique purpose that comes with racing unattached as a pro.
Finally, the ATC is the profit model that track needs. Pure track and field is primal to man, anyone easily understands the premise of track. However, the pure track meet is quickly uninteresting because in non-championship meets, the motives behind the athletes are unclear to the spectator. There are countless heats and flights. One great performance is quickly forgotten and overall meaningless to the rest of the meet. The ATC provides the meaning, every jump, every race, every throw, is adding towards this final conclusion that the spectator can share in. Once the fans attention is grabbed, the sponsors will take notice and begin to market towards them through the athletes. Now an athlete that isn't an Olympian, but is a hometown hero can get a shoe commercial because the whole city knows who he is. Health and Fitness are huge industries and track athletes are the perfect models, but the recognition is lacking. And if the USATF plays their cards right, this league could raise the attention of track in general and lead to increased appreciation of USA Championships/Track and Field in the USA in general.
And once the attention gets to a national consciousness level, the sponsors and media networks will provide enough cash-flow for the athletes and the league. All of a sudden, elite athletes will expect to get in this league to augment their income, athletes from other countries are now trying to get their shot in the league. The talent level is now crawling with Olympians and the fans cannot get enough of it. The fans do not care about PR's, but WR's and NR's do get attention. They care about winning. Once they have winners, the marks will start to make sense. The league will get to the level of MLS and Track will be the 3rd or 4th sport in some cities.