I damn near changed banks after an issue with a data leak that was far less serious. The only reason I stopped is they knew precisley who was potentially affected, informed me immediately and then took steps to make sure none of it came back to me. That is, any charges I contested would be instantly assumed fraudulent unless proven otherwise (not the status quo for debit cards by the by) and I would have no liability for anything potentially related to the mishap.
The big question in this case is does the other companies have thousands of hackers on their back :P. A company with the worst security ever, if they dont get attack, they arent going to leak any kind of informations.That doesnt automatically excuse Sony, an investigation is needed for sure.
Between, according to Sony, they did tell their users when it appear the data could have been compromised. An investigation is needed to determine whether they are lying or not. Personally, I dont understand why they wouldnt tell their users sooner if they knew sooner. But yeah its a possibility.