[inopinatus]

There are workflow issues to generalising the case. In particular, since this is a devops issue any such solution has to be based on satisfying the needs of developers (e.g. ease of deployment, version specificity), and the needs of admins (ease of patching & audit, dependency management) across a wide variety of packaging mechanisms for both base OS and many language-specific ecosystems.

It's no surprise to me that the unit of deployment, for many sites, is becoming the virtual machine template. Since you don't even need to bother maintaining it; just keep your data separate from your code, rebuild the image when necessary with latest libs & pkgs, and throw away old ones. This is how many PaaS providers are doing things.