Bottom line most people aren't going to buy a car they don't want just because you put $7500 on the hood, particularly when that barely offsets the higher price relative to a comparable ICE.
Some people seem to be having trouble with this, so I'll try to make it very clear. The federal EV credit doesn't make people want to buy an EV. It instead enables those with lower incomes who already want an EV to buy, or at least lease one (in which case they then get the opportunity to buy the vehicle for the residual). If you are affluent enough to scoff at the $7500, then just take my word for this, instead of scoffing because it doesn't make any difference to you, personally.
Ironically enough, you can only collect the $7500 if you had that much tax liability to begin with, which means your household income is probably above the $100,000 mark. Not huge if you're moderately well to do in California, but for lots of areas, it's unlikely. For anyone above that mark, no the $7500 doesn't matter.
The exception to that is leases, of course, as that amount is applied to the lease, and that is most certainly helpful for lower income people. It also helps people such as myself to get a super cheap Leaf used. (So in my case, I bought my 2012 for $6,000 instead of the $13-14k it likely would have been if these credits did not exist.)
I get what you're saying, but unless the person is leasing the vehicle, it's unlikely that a person of a lower income could take advantage of the credit or even still afford the car even after the $7500 credit. I forgot where I read the stats, but I remember owners of the Nissan Leaf having a higher average household income than the US median.
Pulled the trigger on going EV on 10/2016 with a 2012 Leaf, and a Tesla Model 3 reservation expected to receive in June 2018.