Is there no great architect in the sky? Is there no software god after all, looking down, punishing sloppy engineers and granting blessings to thoughtful engineers? How else to explain this injustice of sloppy engineering eating the world (to say nothing of JavaScript)?
Especially when you consider this over the whole of Python's lifespan, which very, very firmly includes many years in which multicore was simply not a thing, followed by some years where it was a thing but it didn't work very well anyhow at the OS level so who cares what Python does with it.
It is not as if back when it was put it the choice was either to use a GIL or to correctly write a multithreaded interpreter and fix all the 3rd party libraries at the time for exactly the same cost. The latter option was orders of magnitude more expensive, and harder then than it is now, with better tooling and more collective developer experience. The choice of not using a GIL, rather than being some sort of nirvana that we could just be in if they hadn't chosen poorly 15 years ago, could well have killed the language. We don't really know. I do know that a programming language that just sort of breaks every so often when you use threads and there's absolutely nothing you can do about it from the Python level is not a very appealing proposition and it's hard to know how badly this could have hurt the language.
And Python of all the languages now has a well-justified fear of breaking everything and demanding that everyone upgrade.
So, to put this in a nutshell, if you believe the GIL is simply bad and should never have been an option, you have a very immature understanding of software engineering, especially in the light of being the leader of a very very large community who will be impacted by your decisions. It may not have been the only choice, but it was a good one, and regardless of what decision was made 15 years ago there would be some consequence to deal with now. No programming language community can be expected to get everything right in 2003 that the people of 2023 will want any more than we can expect any current programming language to be the perfect programming language of 2043 right this second.