> More companies should follow this approach

No, the law must mandate that. You either provide active support, or if you end it you must open-source all tools necessary to perform maintenance. It's one of those things that has to be mandated by law to provide a uniform floor on all companies and manufacturers, like food safety laws, fire codes, or accessibility for the physically disabled.

This comment strikes me as absurd. How exactly would you propose that something like that be done?