I mean, Guido had a 2021 Faster CPython presentation where they claimed "5x in 4 years (1.5x per year)"[0]. Developers have significantly walked back those expectations since then.
[0] Github slide deck https://github.com/faster-cpython/ideas/blob/main/FasterCPyt...
One important caveat to remember is that this is before a lot of the work on free-threaded python started in full force. A lot of cutting edge work had to be done to support this in the GC but this came with performance penalties. As a result, the trajectory of the Faster CPython effort changed quite a bit.
Didn't help Microsoft axed several folks on that team too...
> Didn't help Microsoft axed several folks on that team too...
Only after the four-year period was over, during which they only delivered a 1.5x - 2x speedup instead of the projected 5x.
Sure, reality is a harsh mistress, but those were really optimistic targets which were used to frame a lot of the development efforts.