IPv6 adoption has been increasing linearly for about 15 years now. Growth rate is about 3% - 4% a year, not compounded. Some long infrastructure transitions:

IPv6 adoption has been increasing linearly for about 15 years now. Growth rate is about 3% - 4% a year, not compounded. Some long infrastructure transitions: - Railroad freight car bearings. First roller bearing freight cars, 1948 ("Roller Freight!"). Roller bearings mandatory for car interchange between railoads, 1994. - 100 VDC power distribution. Started in the 19th century, still widespread in the 1950s in older cities. Grand Central Station finally got rid of the last DC circuits, other than subway traction power, in the 1990s. (Grand Central had everything - 120 VDC, 60Hz AC, 40Hz AC, 25Hz AC, 600VDC, and a basement full of rotary converters.) Transitions that should have happened by now: - Europe is still using those crappy buffer and chain freight car couplers. Everybody knows they're crap, but the Eurocoupler initiative of the 1970s failed and the Digital Automatic Coupler is still slogging towards implementation.