The Model S is a single model that actually competes against a slew of other models in multiple segments. As such, comparisons are fraught with difficulties. Size-wise, the Model S most resembles the BMW 6 series or Audi A7's. But the actually competes against the typical eco-cars (Prius, Volt, Leaf), mid-sized sized luxury, sport, and large sized sedans (BMW 5, 6, and 7 series, Audi A6, A7, and A8) and so forth. You can go look at the market data (a bit old now) with the list of conquest cars. It is notable to compare it to the large luxury sedan segment mainly based on price, but it really doesn't compete against Audi A8, Mercedes S class, and so forth. That's not its true conquest vehicles. It tends to draw a very wide mix of buyers, many buying the priciest car they've ever bought. In terms of overall volume it truly competes against, I'd take the upper end of the BMW 5 series, the 6 series, and a sliver of the 7 series in terms of sedans, but really Porsche is often a conquest brand almost as much as Toyota. Throw in a mix of Volt/Prius/other eco/hybrid vehicles.
As a result, it is really segment leading in terms of ASP, but that's a bit misleading due to the lower TCO, people likely actually compare it at $10k to $15k lower. The total addressable market should be much larger than the current amount... Service Centers, Superchargers, and Galleries are still missing in a number of regions even in the U.S. and therefore even Tesla's most well developed markets, there's a lot of room for growth.
Achieving that growth in 2017 is a different matter. It could be that the remaining addressable market will take a lot of convincing... in terms of crossing the chasm, we likely still haven't crossed the chasm for all markets except Norway and California. And even those, we are likely at the earliest of the early majority.
It might also be that Tesla will need many variants in order to really address the market. The back seat of the Model S is a bit cramped like the BMW 6 series or the Audi A7. These are sporty versions of their sedans and have correspondingly much smaller sales volume than the BMW 5 series or the Audi A6. A redesign of the Model S after the Model 3 might be necessary to truly capture the mid-size luxury sedan market.