I miss the wide diversity of operating systems and computer architectures that we had in the 80s and 90s. It was exciting watching them all compete with each other and cross-pollinate good ideas.
It also still blows my mind that out of all of the Unix vendors from the 90s, it was Apple that became the dominant Unix workstation vendor.
It also still blows my mind that out of all of the Unix vendors from the 90s, it was Apple that became the dominant Unix workstation vendor.