That's not really a fair point. I think it's better to look at their market segment. The people who want a nice-looking (luxury) car, roomy with 4 doors who are environmentally aware. That being said, there are/will be numerous established players (American, German, Japanese) who will provide a vehicle that could fulfill this market segment in one way or another.
Keep in mind consumers with certain existing brand loyalty are more likely to buy from your trusted brand before buying from a relatively unknown car maker. Especially, one that doesn't have as many dealership footprints around the country, which further reduce the probability of a sale.
You can make the argument of Ferrari who have a niche market and who have stayed in the business despite all the competition. However, Ferraris had/have a long history of racing history and certain brand around handling and driving. They are targeted to that audience. Tesla sedan is marketed to a whole different segment that could as easily buy a BWM, GM, MB, VW or Lexus before they would buy a Tesla.
Tesla is innovative, but their innovation is not something that can hold everyone else back. I've seen the car and how beautiful the interior and the center console is, but it's not enough to hold the competition back.
Lastly, Tesla is yet to offer a leasing plan. Nissan is offering an amazing deal on their Leaf. I looked at it and my projected fuel cost saving was roughly the same as my lease rate. Meaning I could drive a car for FREE for 3 years.
So now Tesla is going to move to a saturated market and they need to start adding marketing costs, dealership expansion costs and other unseen expenses to maintain their sales and suddenly they are not going to have the same profit margins and are going gradually get squeezed out. Their only hope is to sell to Toyota or MB who already buy components from tesla.