I don't know how you measure "impact," but this doesn't sound right to me. If you took away all the GNU code from a GNU/Linux system, my guess is that you would no longer have a working Unix system. I don't think that can be said of the other organizations you mention.
And if you mean social impact, I think it would be hard to overstate the role of GNU in getting the free software movement going. Yes, there is an ecosystem of self-sustaining projects and organizations now; but I have my doubts whether any of that would be there without the initial efforts of GNU.
By that line of thinking, why call it "Linux" (or anything else) either? I agree that "GNU/Linux" sounds kind of dumb, if that's what you're driving at -- but I'd be happy to call the operating system "GNU".
Why do we call it aspirin instead of acetylsalicylic acid? It's familiar, easy to spell, and easy to remember. It's an accident of history. What would be accomplished by renaming it?
Most people in the world don't call it Aspirin, as that's a registered trademark of Bayer AG. The trademark was voided in the U.S. during WWI and never re-granted.
Bayer holds the trademark for Aspirin (Capital A) in Canada (and others).
The trademark is void in the US (and others)
When Canadians that I know (incluidng me) say "aspirin" we mean very deliberately "Any kind of ASA - and if it's not the generic stuff you're some kind of weirdo who likes to waste money" - but we still call it aspirin.
Brand names don't, of course - they list ASA as an ingredient... but I've never in my life heard someone ask if I had any ASA.
Different experiences. The first time I had someone ask me for some, I was confused: I didn't know what it was (I had just immigrated from the US). But I've had more than a few people refer to it as ASA in the thirteen years I've been here.
And if you mean social impact, I think it would be hard to overstate the role of GNU in getting the free software movement going. Yes, there is an ecosystem of self-sustaining projects and organizations now; but I have my doubts whether any of that would be there without the initial efforts of GNU.