As someone who has driven a Model S, the experience is so much better than an ICE vehicle (acceleration, technology, not having to go to a gas station), that the other entry level luxury vehicles, while very nice, feel very obsolete and uninspiring.
I do, however, that the market will be much bigger than anyone anticipates because many will realize the cost is similar to a Camry after gas savings. I also think they’ll drive one of these vehicles and realize that it’s a much better experience than other vehicles.
Luxury car manufacturers are very good projecting who their customers aren't. To a certain extent, a car purchase says something about who you are not as well as who you are. A lot of iPhone buyers are saying I'm not an Android as much as they're saying I'm an iPhone user. A lot of Tesla's target customers for the Model 3 fall into the same category.