Unlike physical goods where the customer can manufacture their own replacement parts when the product is no longer supported, software is bound with a license that doesn't allow the customer to produce their own patches. I would like to see end of lifed software available to customers as part of an escrow process that allows them to build their own patches if they are needed.
This sounds alot like the philosophy behind open source software, to allow the customer to customize or change a product to meet their needs or fix some problem. With commercial software though, there's too much value given to the intellectual property of the code. The model expects that all things have a finite lifespan, a planned obsolescence, so that the company can sell more product. Companies sometimes donate their end-of-life products to open source community or similar efforts but this still seems to the the exception more than the rule.