[netheril96]

The idea that language and its implementation can be separated is only theoretical. In practice, the adoption of a certain language is highly influenced by its implementation (and ecosystem).

The language improvements are nice. I know this because I started with Python 3 then switched to Python 2 and missed some of the goodies now and then. But the language improvements are not enough to overcome the breakage of backwards compatibility. Only a vastly improved implementation (that is not backported to Python 2.7) will.

[kylebgorman]

Python is notable among its peers in that it has a well-defined spec that is not just a list of bugs in the reference interpreter. It is thus important to note that some of the non-reference interpreters do already have the properties requested in TFA, but for whatever reason they haven't supplanted the reference implementation. (I suspect that the ability to drop down into C/C++, link against preexisting libs, or use tools like Cython and taking advantage of the compiler's optimizer, is actually more important than, say, the average PyPy speed boost. Certainly it is for me.)