Do you know that, or do you suspect that?
> how many miles are driven where AP/FSD would refuse to engage
I've used FSD for the vast majority of the nearly 40k miles on my 2017 Tesla model S. Highways, boulevards, side streets, even dirt roads on occasion.
It's a powerful but subtle tool. Used correctly, I have absolutely no doubt that has made my driving experience safer and less stressful.
It definitely requires an engaged, alert driver.
Where I suspect you and I agree is the impact of Musk's language and claims around the technology.
If he would fully shut the hell up about it, I think it's quite likely that there would be way less ill will toward the product.