I've been reading the same news sources for a while now, Hacker News included, and it seems like every other day there's a report of another major break in. I don't think this is all due to LulzSec, so what's the deal?
Rather, you should be asking why high-profile, extremely public break-ins are on the rise. The number reported by the companies affected has been extremely low - the same level as normal? - with the vast majority reported and publicized by hackers.