Immeadiately, I can't lie, I'd be happy. I'll admit,, I used to be a Nintendo fan, and lamented the 64 losing to the PS1. But, now that I've stepped back, I can look back and see it as a good thing. Nintendo got arrogant, thinking they could do no wrong. They needed the correction. That is the boat Sony is in right now. They need the correction of a PS3 failure to realign themselves for a better PS4.
On a deeper level, I'd be concerned. Nintendo was at least able to profit off the 64, which Sony is not doing with the PS3. If it were to die off, I'd be more worried about Sony completely removing themselves from the market (or worse, see next paragraph), causing a loss of competition. The competition is what breeds innovation. If Nintendo did not get the correction from the PS1's victory, we'd probably still be gaming on cartridges. Without the current Wii correction, controllers would just get more and more buttons. I don't want gaming to feel old; in fact, it's the old feeling that was slowly starting to push me away from gaming in general. (I can say that if it wasn't for the Wii and DS, I wouldn't be here making this post.) This isn't to say that I can't appreciate the older styles; the innovation also made me go back and get a bunch of PS2 games. But people need to be thrown something they don't expect on occasion- that's what innovation does. And it will only come from competition, which Sony is one facet of for the market.
For lasting impact, it's hard to say. If the PS3 crashes bad enough, it could take out the Sony corporation. This will ripple worldwide into deepening the recession we're currently in. I'd like to hope that Sony could salvage enough to stay afloat, though there would still be some jobs lost. A bad crash would result in selling off of Sony's game studios, of which Microsoft would probably be the buyer. A slow burnout would probably relegate Sony to Sega's position- making games, but no more systems. (I also feel this would be best-case for Sony.) I will say that I do not see Sony just folding up the doors on the gaming division, though; they need to salvage what they can. The additional write-off losses for closing a division is something they simply can not afford to do right now.
Of course, this hasn't happened. Ideally, it won't.