> but as someone in the professional computer security field I know that any company or state/department/organization can be hacked by a motivated attacker.
You seem to give Sony too much credit, and also forget that they had a file server with open internal access which had a directory called "Passwords" which contained a plain text file with all the credentials to their internal servers.
That's something I'd expect to see at some small business with no professional IT on staff... certainly not from a multi-billion dollar company with thousands of employees and a full-time professional IT staff.
Sure, the attackers may very well have spearphised their way inside, but once inside, they didn't have to go through any of the normal hassles of island-hopping with more exploits, etc. They just logged in like they belonged.
Motivated attacker or script-kiddy, once inside, Sony made it awfully easy.