I think the reason it's taking so long to get back up (after all, they're the ones who took it down) is because of all the oversight they're facing from watchdog groups and the US Federal government. They probably could at least restore multiplayer or something with no problem, but they don't want to make any moves until they know 100% sure that government(s) won't accuse them of being negligent.
Also, the hackers wouldn't just be facing criminal charges, they'd be facing civil suits for tortious interference with property. And that's a lot of money in those cases. Sony and third parties are losing tremendous dollars from a pretty stable revenue stream - I think Capcom said hundreds of thousands to millions of dollars. I can't imagine how bad this is hurting the smaller indie devs PlayStation supports with their pub fund in exchange for exclusivity. I really hope whoever did this gets taken for every penny.
It sucks because I was all set to start Xenogears, now I can't buy it on the Store. I guarantee you there will be crazy connection errors and slowed service b/c everyone will be buying the games they wish they had before the blackout.