Consider adding an option for "Wouldn't purchase". Our car is a daily driver. I'm all about convenience and tech. With the ability to charge at home, there is no way I'm stopping at a charger during the week to charge. I'm not sure I see a time in the near future it will go on a long road trip and need any SC. I drive about 200 miles to see family and have a way to charge there. Compared to gas savings I'll do what I can to charge at home, it's about convenience even paying for the juice myself.
This isn't my situation, but if I had a need to drive a lot more and covered a several state area in a sales job or something like that, my answer would change. I'd likely be dependent on the SC quite a bit. In a case like that I could see lifetime being worth maybe $2000. I'd have to think really hard about it though.
I'm sure Tesla has many number crunchers working the numbers to know how much a car will use over several years and they know how to price this, I kind of wish they wouldn't sell it like this though. There is no way to truly control future costs of building SC's and the price of electricity, so just continue to build SC stations and charge accordingly to what it costs to run them to break even.