You can still get software that installs and works perfectly on Windows 7 (released 16 years ago). Good luck finding software that even installs on Snow Leopard (released 16 years ago), let alone works well.

Microsoft still manages to do 'cool stuff' at the kernel level; IO Rings, VBS, Rust, etc.

Only thing I see on the Apple' what's new that looks interesting is Metal updates. Most of the rest is UI.

I mean OS updates are necessary, from security updates to support for new hardware. Stuff like init scripts were a suboptimal solution to begin with, it is not like that old stuff was a good solution. Xorg also doesn't fit how modern computers work, and is merely a collection of bandaids that is inherently unable to reach sane security by todays standards. So its not like progress is entirely superficial. And also with Flatpak there has emerged a way of shipping stuff such that used libraries can be shared but do not have to be, and every app can move at its own pace without conflicting with other apps or the OS. So at least in Linux land, especially in the last couple years, there has been great advances from a technical point of view. And those tackle also the problems arising when a huge number of indipendent parts come together, which were naturally very pronounced for Linux in the past.

Yeah we are in this situation right now with an App, we literally can't update it unless we target a more modern version of the SDK, which introduces breaking changes

I’ve got a MacBook and Mac Mini stuck on Monterey (12), and an iMac stuck on Big Sur (11). I’m pretty much dead in the water when it comes to software compatibility, unless I want to put Linux on them. Even homebrew gives me a warning that they’ve stopped support and to expect everything to break. It’s a sad state of affairs.

Linux runs fine on my wife’s old (2013) MacBook. It’s more than fine, actually. I have Arch and Niri on there, and it makes a great SNES emulator.

The immutable and atomic movement in Linuxland is very exciting. Cloud native distro building with docker/podman in CI pipelines is just insane: Building+testing+deployment with ci/cd can now not only be done with some python package, but a whole distribution. Also Wayland, Pipewire, Flatpak and Btrfs are great stuff. Of course they don't get developed in one release cycle, but in recent years they made large leaps and became default on many distros.

Not Linux, but I still look forward to window managers and Neovim releases. The Cosmic desktop also looks promising, though I’m not using it until it has a scrolling window manager available for it.