> Python works on every platform, and distributing is just a "pip install" and "pip install -u"

Until you have a dependency which has a C dependency (like a crypto framework, SQL connector, etc). Suddenly you need an entire compiler toolchain, dev dependencies, all the library headers, and a decent amount of time. Also the errors thrown when these compile steps fail are anything but helpful for new users. If you are lucky there is already a wheel for your platform/arch.

> Surely thats easier than "Download the correct binary for the platform, unzip it, change permissions, add it to your path, then do it all over again for every update"

This is trivial to automate using a script and has a ton less failure modes to deal with than Pip would have (do you have the correct Python version?, is there a compiler installed for C modules?, etc).