I don't think it will be *years*. Before being announced Elon said that V3 sites were cheaper for Tesla (I can't find a reference now but I'm not sure if this was to build, to operate, or both). I think it was something to do with the shorter charger times mean fewer stalls to serve the same number of cars as V2 (or the same number of stalls to serve more cars) and the fact that V3 is more easily able to integrate battery storage in to each site (reducing peak energy costs, and - entirely my speculation - allowing the batteries to provide revenue from grid services in times of low usage).
In other words, V3 will be the "new standard" and all new superchargers will be V3 after a certain point in time. (Exception - in the US they still have the 72kW urban superchargers, that we don't get here - and probably won't as they only have room for one cable)