EXCEPT, for the fact that with the desire to cache things, it would be beneficial to “hook” into the lifecycle of a package install. However I know that there are other plugin systems out there that would like to also be able to do that (Twisted Plugins come to mind) and that I think outside of plugin systems, such a mechanism is likely to be useful in general for other cases.
So heres a different idea that is a bit more ambitious but that I think is a better overall idea. Let entrypoints be a setuptools thing, and lets define some key lifecycle hooks during the installation of a package and some mechanism in the metadata to let other tools subscribe to those hooks. Then a caching layer could be written for setuptools entrypoints to make that faster without requiring standardization, but also a whole new, better plugin system could to, Twisted plugins could benefit, etc .