Oh and I figured out how the wired matrix infrastructure could be damaged as badly as some people make it out to be. In some areas where the right of way for power lines and such are restricted, they will sometimes run the power lines and fiber optics as a bundle. Not just on the same pole, but actually a combined 'smart' cable. In those areas where the grid isn't physically separated, a power surge could blow out something on the far end, which lessens the capacity of the system, causing the next weaker node to blow, etc. in a cascade failure. Since the power line and datalines are bundled together in those areas, when the power line blew, it melted the fiber optics as well.
Note that in many areas, the expensive 'smart' cables aren't necessary so the 'last mile' of the cable is likely separated and sent out to homes that way. Most likely, the transformer stations where the power gets stepped down is where the cable splits and also where the physical damage was apparent. Getting power up and running on the grids would be relatively easy, since the cable is fairly basic. However, re-running all that 'smart' cable (or even fabricating it in the first place) would take too long. So its a matter of get power up in a week, or get everything up in 18 months.
A major issue with this theory is that it necessitates that the gridlink system build into the highways of Seattle is completely fried and would mean digging up the entire roadway to replace. Local municipalities might be able to cobble together something, particularly downtown Seattle, where the gridlink is accessible from below, but the vast stretches of highway connecting the metroplex would likely be a non-starter. That would seem to mean more gas powered cars again, since electric cars would have to rely on battery power. That means more pollution and gas prices going up.
That doesn't address the data loss though. If people lost SINs and whatnot, that had to be a direct assault on the SIN registry. I think that whatever vulnerability was exploited or whatever safeguards were put in after the Crash, these are the methods that allow the Erased quality to be effective.