How do you require a certain level of service when the company that made it goes out of business? Or when employees with essential knowledge leave the company? I've been working in software for a long time, and everywhere I've worked, losing someone knowledgeable about a product is a big blow to future development because a lot of important knowledge is only in their head, leaving future maintainers to do a lot of reverse engineering. Requiring documentation wouldn't work because any company that had strict enough requirements would have a very hard time hiring engineers willing to spend so much time documenting every little thing.