Maybe, but when you buy your car it's important to realize that these $7,500 are not just free money, they have a direct impact on your car resell value.
So if you buy a leaf that starts at $30,000, get rebates to $20,000, you must remember that since anyone can get it new for $20,000 that's the actual "new" value to take before you apply depreciation.
In other words you're not really buying a $30k car for $20k, you're buying a $20k car.