This seems largely to be about security by obscurity.

I was hoping it was gonna be about how our modern practices are making things less secure.

For instance, we claim we need to be able to rapidly update clients so that we can patch security vulnerabilities as they are discovered (often without involving the user at all). And there are a lot of companies that have an incentive to push this narrative because they have products which facilitate this whack-a-mole approach to security. But there's no reason to believe that new software is more secure than old software. Old software is just more likely to be known to be insecure. So anything written before it became trendy to update without your user's consent is more secure in at least one way because it is not configured to automatically update to whatever comes down the pipe from "the vendor".