Some NASCAR fans have speculated for years that the sanctioning body will throw a caution flag late in the race to tighten up the field. This is particularly true when the cars have become spread out and cameras struggle to find anything on the track large enough to justify throwing the flag. But there's a big difference between bunching up the field and staging conflicts. There's simply too much risk involved when you have someone driving a car at nearly 200mph on a track with 42 other people also going 200mph.
No matter how much of a crossover their fanbases may have, NASCAR isn't professional wrestling and isn't trying to be. Sure, they encourage their drivers to settle their own disputes. They love the publicity that a good feud will generate. But the reason why those feuds draw interest is because they're real.
If they were to stage some sort of conflict along WWE lines, the blowback from exposure (and make no doubt about it, it WOULD be exposed) would bring down the sport. The France family that owns NASCAR knows this. Brian France may not be his father or grandfather but he's not about to risk billions for an extra half a ratings point.