Based on my research for the Tesla Model S comparison/equivalent car calculator I toyed with the idea of a Tesla "Model T" (pun intended) for taxis...
If a taxi driver driving about 100,000 km every year (~60,000 mi) in Toronto were to buy a Model S today with 85 kWh battery, dual chargers, high power wall connector and subzero weather package, and regularly for annual maintenance *AND* ranger service every 4 years, even a new batter every 8 years (based on today's cost of REPLACEMENT = NEW - OLD and 15% annual price reduction) then that driver would be better off with an I.C.E. car ONLY if that car was GIVEN to him/her together with another $19,000 cash (i.e. it has negative price).
If the car was to be kept and driven as a taxi for 7 years, instead of $19,000 cash s/he should be given $36,000. At 8 years that is $60,000 :)
Why would this be cool for everyone? Other than purely ecological effects, Tesla would sell more cars and would be able to make more infrastructure that would be good for everyone!
Keep in mind that real model T(axi) would be somewhat different than S - more space, less luxury, perhaps more sturdy, could have a room for more batteries. That said, it would really be cool if there could be a battery compatibility with model S as that could affect pricing and make the battery swap more realistic and common!