I don’t think iOS will ever be my only, and there are too many advantages to macOS right now for me to seriously consider switching, or even using iOS as a primary device (unless it was temporary, and I was traveling).
I like a big screen.
I like my Trackpad with Force Touch.
I like multitasking with background processes.
I like my choice of keyboard… with function keys.
I am used to some apps I’ve used for years, along with their keyboard commands.
Many apps I use have no iOS equivalents.
I like to control my files in folders on local drives, and I like the control I have in terms of backups.
I enjoy being able to acquire apps from developers, including apps that Apple would not allow in the App Store because their powerful functionality crosses a line for apps it wants to make available in its walled garden.