I imagine for some end users a lot of this stuff is happily invisible, just like you say. But for me, a few kinds of changes have been highly visible as a user

I imagine for some end users a lot of this stuff is happily invisible, just like you say. But for me, a few kinds of changes have been highly visible as a user: - basically all filesystem changes, especially the mainstreaming of copy-on-write filesystems - not a change, but dramatically better filesystems performance than Windows or macOS has always been noticeable - the addition of cgroups and cgroupsv2, and later user namespaces, which enabled lots of software that I use - all kinds of driver updates and additions, obviously - newer virtual filesystem stuff for introspection, set to replace /proc - addition of KVM! I remember when this was not a given, in the Xen days As someone who uses macOS at work for the last several years, I really miss the Linux kernel when it comes to filesystems, and feel like macOS updates often involve very few changes that I care about or even consider operating system change at all. Most macOS updates are just trumped up application updates. In that way I've kind of felt the opposite somehow, like OS updates on proprietary operating systems feel thin and empty.