Remember the transition of text to Unicode? 32 to 64-bit? Intel to ARM? Y2K?

No-GIL is a much smaller shift. It can follow the same transition path without radically breaking things. And if some things do break, there would be a well-defined way to handle those cases.

We all somehow survived those. Glad to see forward motion on this. It will open up a lot more terrain that has been marked off as untenable.

One of the things about early Swift that they got right was building breaking changes into the promise. Everyone knew where they stood and adjusted just fine. Sometimes I wish Python would take the same path.