For the biggest part of my life it seemed that all these technical accomplishments were the work of untouchable geniuses, but reading this story is also very telling about the value of long-term friendship and financial/societal stability to support each other's explorations.
They confusing Linux and GNU/Linux in that article.
They're not bothering to draw a distinction that almost nobody cares about, yes.
One should make one as it otherwise makes it hard to read, because there is no distinction between the operating system and the kernel. Saying Linux can compile itself is just nonsense as it clearly needs GNU GCC or another compiler. But of course you can have a Linux operating system without a compiler. Using Linux as either Linux the Kernel or a operating system with the Linux kernel interchangably is just imprecise gibberish. Almost as bad as intellectual property.