> since you can't tell what should be removed, or more importantly, what can be removed

Isn't that what dependency detection does? Whenever I'm not sure if something can be removed, I just try to remove it, and if it would break something else, the package manager tells me. I can broaden my scope and see if that's also an unnecessary dependency for something and follow the chain, with it eventually ending up with a set of packages where I actually get the prompt to proceed or not (meaning nothing in it is a required dependency for anything remaining), or I see a package I definitely want to keep around and stop. If I'm interested in what's part of the base system, I just check the metapackage for the base system.

This doesn't sound like something that's a problem with package managers in general compared to maybe some distros just using them poorly.

Curious about this. Usually I try to get an Apt source (I use Ubuntu). Why would I want to use brew on Linux? I stopped using Macs and brew around 2018 when Apple started closing down it's macOS for a few years and got sick of it. Thanks!