This completely wrong. I'm tired of people spouting off this nonsense. If all the pools dropped, people would mine solo.
If you look at deepbit, when it was hit by DDOS, everyone switched. There was no "loss" of pooling.
Or are you assuming all of us mining are NOT greedy bastards and would flounder around saying "AHHH POOLS ARE DOWN NO MORE MINING!?" If anything we are greedy and would start mining like mad thinking that deepbit is down and therefore 1/4 the total pool. (Completely wrong.)
No, there's no worry about DDOS and then someone taking over the network that way.
Yeah, one pool down means everybody switches. But, when all pools have problems?
I am not sure, but a lot of people with < 1GH/s would not go solo. Waiting a month for single block on average requires a lot of patience and good nerves to not loose faith.
If the pools would not be invented last year, I guess the network would be 1/10 or less than it is today.
Plus, the attacker can "prepare" his own new pool while attacking all remaining. All would switch to his pool, and he would easily gain >50% of network. You would not know at all, he can "fake" his pool stats. Then, he rules the network.