Lets be honest here.
NASCAR has lost its spark to a lot fans over the course of this season and they need something to reignite it again. Busch versus Larson is probably the best case scenario for the sport right now, especially since it allows a new driver to enter the championship picture, it could also make for some great off track moments as well.
In the end, its usually a bad idea to pander to your fans, but if NASCAR and fate will allow this rivalry to blossom, it will be a huge turning point for the sport and could allow them gain a ground swell of support. The best part of all this however is the fact that its not really pandering when you consider that these type of rivalries are what NASCAR was built upon.