That analogy doesn't really work - software doesn't get worn out from interaction with users. If software is working and in use, then it's age doesn't matter.
Evolution/flux is not the natural state of all software. I've seen plenty of business/enterprise software which has continued to provide business value for decades without structural or architectural changes.
Lots of security patches and infrastructure are held hostage by breaking changes to APIs. Eventually you have to upgrade, and the longer you have put it off the more painful it will be.
And as we've seen with old video games, there are lots of timing problems that you simply never encounter on the original hardware but are impossible to ignore on recent vintage hardware.
We shouldn't really be treating software differently. The liability for a mission critical system that works but cannot be repaired climbs over time.
Just because it works doesn't mean it isn't broken.