I don't have a copy of the old website pages. As I recall, the Model S specifications page stated something like "Free long distance driving on the supercharger network". [Maybe someone has a copy of the earlier website pages???]
If you look back at Tesla's initial 2012 & 2013 announcements (
first announcement), the superchargers were being provided to make "electric long distance travel at no cost".
In the
second announcement, it states "Supercharging enables Tesla Model S drivers to travel long distances, for free, indefinitely."
In the
third announcement on the first Norway superchargers - "...that enable Model S owners to conveniently travel for free between cities along well-traveled highways throughout the country."
In the
fourth announcement for the expansion of the Europe network - "... will offer Model S owners free, fast charging for convenient long distance drives throughout Europe … All our Superchargers are located near amenities like roadside restaurants, cafes and shopping centresso that road trippers can stop for a quick meal while their Model S charges for free."
And in the
fifth announcement (in October 2013), it states that the newest superchargers "enable Model S owners to travel for free between San Diego, California and Vancouver, British Columbia."
It wasn't until later that Tesla began talking about urban superchargers, and then began planning to start charging for use of the superchargers, with some charging provided free with the purchase of a Tesla.
Tesla initially included supercharging as standard on the S 85 models and it was an extra cost option ($2500?) on the S 60 models. Tesla later changed the policy to include supercharging on all models. Based on the initial S 60 pricing of the supercharging option, plus the free lifetime long distance supercharging, Tesla evidently believed the per car cost for the supercharger infrastructure and energy costs, over the lifetime of the car would be no more than $2500. Which is likely true if used only for long distance road trips. But if used for daily supercharging for commercial vehicles or for all charging of vehicles without access to overnight charging, the per car cost would clearly be higher.
Tesloop reported they had a Model S with over 400,000 miles, estimating they saved around $40,000 in fuel costs, compared to an ICE. Doubt Tesla expected anyone to use a supercharger that much...
Agree with maximillien that limited supercharging is likely to be included with a Tesla purchase. Though customers it would look better if the amount of free charging was listed in distance (rated miles or km), and not in a charging cost credit or KWh per year. It sounds more impressive to say "1,000 free supercharging miles per year" than a "$100 annual supercharging credit" or "400 KWh supercharging per year". And it might also make sense for Tesla to provide a larger amount of free supercharging on the higher priced models (3 performance, S/X/Roadster 2.0) than on the $35K Model 3.