A phased roll out is typical.  Same happened when 1G, 2G, 3G and 4G/LTE rolled out. As I have stated before, this cycle (roll outs) will be multi year, I would guess it would go on for some 3 to 4 years in the US. Probably longer cycle for the rest of the world, developed countries first then developing and last third world coutries. Of course, the size and frequency of roll outs could be faster or slower, does the article mention that specifically?