Recalls aren't just something that magically happen. Usually there's an investigation (by the NHTSA, or the company themselves). That investigation concludes that a recall is warranted or necessary and, in the case of voluntary recalls they do a cost to benefit analysis (like how Ford did when the Pinto was a bomb just waiting to be rear ended, and they realized they would save money by not recalling them).

But the NHTSA does force quite a few car manufacturers to do mandatory recalls regardless of whether they want to or not, usually to do with health and safety. You know. To prevent the Ford Pinto scenario.

So it's not so much what they aren't recalling (although I'm sure there's quite a lot). The real question should be, why do they have so many recalls? Why aren't they fixing the problems before they public gets a hold of these vehicles. And it's not just Tesla we should be asking that question of.