Hmm, let's break this down. First, PS3 is successful, famous for being unhackable, then an exploit appears (again). Unlike before where they block it with an update, they take out OtherOS altogether. That's where things begin - the people who actually used it want to get it back, so they start using their skills and talents to break the security. Few months later, after many outcries and threats to sue (with some actually attempted - I can't remember how it went), someone finally finds a way in and tries to make money off it (Jailbreak). Clones spread like wildfire and Sony try to get them banned in every country (and fail in Spain to my amusement). The PS3 scene really gets everybody's attention then and things take off. Not that long later, PS3 gets broken wide open.
To fix things, they need to learn their lessons from the experience. Firstly, putting OtherOS back will not do a thing - it became too late for that the moment Jailbreak got announced. Secondly, with a 40 minute tour through the PS3 hierarchy and how it broke down, they should take that to heart and rebuild from the ground up. As Sony announced, that means updates. It means a major update, probably to v4.0, and if they don't find some way to completely rebuild the entire PS3 system (considering that they keys to the system are public), it'll happen again. If they do rebuild the entire system, and fill up the holes in their security, they'll probably be successful in recovering. All they can do then is hope that their new games that require the new version to run will be awesome enough to make people want to update to it. It could happen... but probably not. Either way, I hope Sony succeed. I'd rather give my money to Sony than Microsoft (even if I may take this opportunity to try all the small older PS3 games that no shop seems to sell anymore).