All of the things you mentioned regarding the slow start of the S2 model are correct. It doesn't however change the fact that the Elise is Lotus Cars (not engineering ) main source of income. Yes Lotus is planning other models, as I stated before, however knowing the way that Proton has handled them in the past, if the Elise was to suddenly tank, you'd see the money pulled. Fortunetly, Proton has committed the funds to the intial engineering studies on both the 260 and new Esprit and both should be shown in show version within the next 2 years or so. This is some insurance that won't happen but in no ways a lock. Lotus has abandon the US market before (1981-83), and would do it again if it found the hassle too much.
Regardless of how they are selling, and they are selling very poorly btw, the VX220 has compensated for the drop in demand for the Elise. The S1 was designed for 700 units per year while still under ownership of Artoli. His expectations for the car and the company were quite different than the current ownership. That car was designed to pull in profit at much lower numbers than the current car, just as you stated.
The MR2 and S2000, both cometition for the Elise, don't sell in the 10's of thousands in the US but actually closer to the 5000 units you mentioned for the Elise. Worldwide those cars sell over 10,000 I'm sure but not here. Speaking to a client who owns a Toyota Dealership, his understanding is that the MR2 Spyder is imported into the US at a rate of 3500-4500 per year. Based on the resale values of the car, I can believe that.
I agree, the M260 will be more of a GT and will likely get some form of slush box. What do you think of Audi's unit that they are using on the TT? It is certainly different from the other mentioned up to now.