It's actually really interesting that you make a comparison to operating systems. I helped get ReactOS started in the late 90s, because Windows was so dominant and there was a tremendous lock-in effect because of the software and drivers that were Windows only. However I still think a clone was not the best direction (I left the project ages ago), and that interfaces to other OSs such as Linux are better. Although I didn't come to this conclusion immediately, mainly because driver APIs seemed difficult to abstract to another OS.
That said, Linux has made tremendous strides and WINE has helped it along. With Web 3 you don't have that lock-in effect, so the ideas are flowing more freely. That's why I think Web 3 is different to the OS analogy.
To start, here's my counter-argument: We're almost exactly 6 years from the release of bitcoin, and it's still dominant by market cap. We either nailed it the first time or the best has not (yet?) won. We're 50 years into computing and the dominant operating systems are from the same companies that dominated ~40 years ago. Did we top out on ideas then?