> New versions of CPython come out regularly, always adding many new features, and PyPy struggles to keep up, is always several Python versions behind. If you w

> New versions of CPython come out regularly, always adding many new features, and PyPy struggles to keep up, is always several Python versions behind. If you want you Python software to be PyPy-compatible, you’re much more limited in terms of which Python features you use, and most Python programmers don’t want to have to think about that. Nothing can be further from the truth. A small minority, in any language, not just Python, will use the most recent version. In any language community, the most used version lags several iterations behind the most recently released. In a decade and a half of working with Python, changing plenty of companies and positions, I've never been in a situation where I was using the newest version right after it was released. Not for the "production" environment anyways. The reason PyPy is not popular is... if I had to guess that Python is a first language for many programmers (i.e. the its audience is mostly not very knowledgeable in general, and will struggle to install a Python, installing a special kind of Python will be too overwhelming for them). Python is also a popular language with people who aren't professional programmers, eg. researchers, statisticians. In many places where Python is used its speed makes no difference, even if its used by professional programmers (eg. various kinds of automation). So, there's no particular reason to choose PyPy. To top this: Python is a common language for OS scripting / automation, where interpreter starting time may be more important than the performance of the script. PyPy mostly doesn't support native Python modules, but even when it does, it offers no benefits in so doing. Finally, there's a low-hanging fruit for any Python programmer who makes Python packages: just run them through Cython. This alone gives a significant boost to speed (and some memory savings). Virtually nobody does this. Which is, imo, an indication that speed isn't important. (Also, fighting Python infrastructure and trying to understand the packaging process isn't for the faint of heart, which underscores my previous point of general low competency on the part of Python users). ---- Bottom line: PyPy doesn't offer anything of value to the overwhelming majority of Python users. It would've been a headache to work with even where there might be potential benefits. So... it's not used. Python's release schedule is laughably bad, and new features are laughably bad... well, worthless for the most part... but they aren't the reason PyPy isn't popular.