It would likely be a blip in the news, and then people would move on, as usual.
Remember the Sony rootkit fiasco? People still buy Sony, and most people probably either never heard of that incident, don't remember, or don't care. Buying whatever the new Sony gizmo of the day is is more important to them.
Microsoft has had endless spyware fiascos, and people still routinely buy Windows, as long as they can play their games or run Office, that's all that matters to most of them.
Then there have been scandals like Enron, where the execs knew that they were doing something that was clearly illegal, and that their company really would be devastated if what they did was ever revealed. These "smartest people in the room" did it anyway.
Corporate history is full of just such deceptive and destructive practices. I'm not sure I'd put Facebook above that sort of thing, a priori.