It is highly unlikely that Sony will waddle away out of the console market due to this, though they probably have sustained a lot of damage.
But I'll bite into your hypothetical anyway. If Sony were to go under, either specifically the gaming division or the entire company (I'll go with the former), then it would have drastic consequences for the gaming industry, not to mention a blow to the economy as well.
If Sony Computer Entertainment (the gaming division) were to go down, thousands, and I mean thousands would lose their jobs. Engineers, coders, PR, QA, marketing, executives, all that good stuff, would be thrown out of the streets without a job. I don't care if you think each of these people are nothing but the bottom scum in the work barrel, thousands would be out of a job, and that's only if SCE goes down not Sony in it's entirety.
Not only that, but dozens of studios would be left without a publisher. Say goodbye to Team ICO, Naughty Dog, Sucker Punch, a big branch of Insomniac (they went 3rd party), thatgamecompany, all the little indie studios relying on PSN. Good bye SOE, Sony Santa Monica, Capybara Games, what have you. I don't care if you think each of these companies put out shit on a regular basis, losing these companies, and subsequently jobs in those companies as they would need to cut costs to accommodate for a lack of a publisher, would supremely suck at the minimum. Depending on their contracts, it would even be hell just to switch to EA or Microsoft or whatever with publishing rights and copyright whateverhtefuck lawyers want to use to gain a few extra bucks.
If this were to happen I wouldn't know how quickly the industry would be able to adjust, but I'd imagine that it would take a long time.
I don't care what side of the "console wars" you're on. I don't care if you absolutely despise Sony, or any electronic manufacturer in existence, or if you rally on under the Xbox/Wii/PC flag, whatever. You cannot possibly deny the impact it would have if Sony had to back out on this.
Obviously, this is all drastic speculation, but Sony is going to be hurt by all of this. I highly doubt that Sony will have to back out of the gaming industry because of this, but it certainly has caused a pretty big dent in their wallets, resources, reputation, and consumers.