I have not yet been to a BOSS race but I will if I get the chance. Nothing at all against them but the reason you would run a USAC race over a BOSS race is cause you want the best of the best with the best equipment. It's really that simple.
I would think they are probably not as worried about each other as us fans might think. However, nothing but good could come from working together for the betterment of the sport. Racing is littered with sanction body conflicts that rarely produced anything positive