Assume, for the sake of argument, that all Linux distributors went out of business and that even the all-volunteer projects like Debian ceased. So, what would happen when your next hardware upgrade broke the Linux kernel? Nothing much. You'd have the source code and every tool you'd need to fix the problem. All you would need is a programmer. If that sounds unpleasant, imagine what would happen if Microsoft folded and your next hardware upgrade broke Windows. Without the source code, you're basically out of luck. Of course, this is purely hypothetical, because you'd already be paying half your staff to deal with the consequences of the latest migration to the next version of Windows.