According to the mighty google (and other HN comments) we are running out of address space at about 1 bit per year or so. So most of us will not live to see the need for 128 bit computers. An interesting thing to think about is this: how extraordinary it was to live through 3 or 4 of these transitions. If we keep running out of bits at the rate of one per year (and we don't go extinct) that means that most humans will never life through any transitions. We are either the lucky ones (because we got to seee so many transitions) or the unlucky ones (because we are the ones who had to cope with the disruptions of doubling pointer lengths.)