Rian van der Merwe has some great thoughts, and choice quotes, on the implications of the idea that "software is never done":
I do wonder what would happen if we felt the weight of responsibility a little more when we’re designing software. What if we go into a project as if the design we come up with might not only be done at some point, but might be around for 100 years or more?
It's strange to consider that software may be among the most complex things human beings have ever created, while also being one of the most protean, unfixed, and ephemeral.