A good argument and a reasonable looking list.
But even more, one might consider that the history of software has to some extent been decided by the implementation or non-implementation of certain clever but quite-hard-to-implement ideas.
What is revision control, make and file system began together?
What if memory allocation wasn’t included in the first otherwise rational OSes (unix and etc)?
What if most of the features of a relational database were implemented without the “rational model” being created?
It’s hard to speculate here because everyone has a slightly different idea of what features are crucial and which would have existed “inevitably”. But none-the-less, I think the alternate-software-worlds view is plausible.
His entire website is great. This is a person I’d love to have on Lobsters.