Totally impossible. Closed source software often contains IP licensed from other entities. Just because a company folds doesn't mean they can violate licensing agreements.
> Just because a company folds doesn't mean they can violate licensing agreements.
It does if that's the law. Every jurisdiction routinely overrules contracts as unenforceable on the basis of some overriding law, so it wouldn't even really be that unusual. Whether it's a good idea or not is another question and one that depends almost entirely on second, third and higher order effects.
There probably is a world where all software is libre software and we still see similar rates of development, but it's not at all clear how you could get there. Especially not if you cared about the damage caused by upending the business models of a significant fraction of the world economy.
The biggest blocker there is probably whatever remaining creditors to the company when it goes under then have claims on remaining assets like the software.
One solution would be putting something in the tax code such that donating the code to an open source foundation gives a bigger benefit than simply writing it off as a total loss and destroying it.