Re: "The only way to do serious computing - servers, supercomputers, science?"
"Servers: The last few decades, Microsoft's proprietary OS and commercial proprietary applications/RDBMS from MS, Oracle, etc. dominated the server landscape;
What are you talking about?? by far the most common type of server these days is a web server, and the vast majority of those run on free software. The only type of server that I can think of that more commonly runs on a proprietary OS is an exchange server. And that's because they're locked in to a particular platform.
" CPython, is licenced in the BSD style. So open source, but not RMS's vision of pure "free software"."
The BSD license counts as free software.