I agree if they simply go away, what they produced should become opensource. Sometimes this involves removing dependencies on proprietary software, which anybody who used the opensourced portion would in turn have to pay to license. So they have to rewrite those parts or make special arrangements. Anyway it's not the slam-dunk you might think. Like after what happens in an action cop movie everybody walks away, but in reality they would spend months or years in court over damages to buildings, passersby getting hurt, etc. Nothing is ever as simple as outsiders think.