> For a Linux distro to achieve this macOS-like consistency, they must have some sort of unified SDK for GUI development or a standard desktop stack for develop

> For a Linux distro to achieve this macOS-like consistency, they must have some sort of unified SDK for GUI development or a standard desktop stack for developers to work against. The difficulty here is that the nature of the Linux ecosystem is that the users are free to swap-in/out alternative system components. That's a very superficial and uninformed view. I can write a Qt app for macOS and it doesn't have the same consistency as an AppKit app. It's also just a framework. I would also argue that lumping Linux distros together makes no sense because it's Apples and Oranges. OP basically needs to compare Desktop Environments to have a sense of what it's like. Personally I think Gnome and the underlying GTK framework is pretty close these days in look and feel compared to macOS. With the 3.36 release it has also gained a noticeable smoothness. They also have a HIG and generally strive for a consistent experience with a design group guiding the development. Fedora provides a very nice out of the box experience for Gnome. So does Debian or Ubuntu.