> It's not so much that as there is the net-negative side effect of having people redo the same work over and over again at their day job or whatever. It horrifies me when I think about the number of hours of people's lives wasted on things like that.

Given that this issue applies to all proprietary/non-opensource software, which is the overwhelming majority of software out there, you can hardly blame GPL3 for this fact of life.

I would argue that in many ways (that vary from project to project) the duplicated efforts are a good thing overall. Now, instead of having one single group or person working on a particular topic, there are many and the knowledge, learning, experience, and expertise that comes from that isn't locked up with only a select few. That can be applied in more areas, used for more things, or carried into other endeavors. It also hedges against all that expertise being lost if the few experts of the original project abandon it for whatever reason.

I don't see all the efforts that go into *BSD, Windows, macOS, etc... as being wasted just because Linux is available, nor would I consider the effort to try something completely new in os/kernel design that starts from a clean slate a waste, even if it doesn't end up becoming wildly popular. Not everyone who has the capacity to work on a duplicate effort would be able to contribute to the original, and the original will never be able to perfectly meet the goals/needs of everyone.

But who cares if someone chooses to redo work they didn't have to? I don't care about that at all. Self inflicted wound.

They presumably can salve that horrible wound with all the money they get (not make or earn, just get) from their chosen modus operundi.