Open source Linux core where installed software may or may not be open source, with an increasing reliance on closed-source cloud applications? Closed source graphics drivers, network firmware, etc? I don't have any statistics obviously, but I would be willing to wager at least 50% of Linux desktops have some closed source installed or some reliance on a cloud provider. Even if it's Flash for watching YouTube videos.
That's still not even close. How easy is it to side-load on Android? Browse the file system? Obtain root access? Recompile and update the kernel? Replace the window manager? Android may be a lot more open than iOS but it's not even close to a Linux desktop.
How easy is it to side-load on Android?: Very Easy out of the box. Just open the apk and the installer will install it.
Browse the file system? Very easy. There are many free and paid file managers. You can also use a terminal emulator.
Obtain root access? OEM unlock bootloader, throw su on the phone and you are set.
Recompile and update the kernel? I has never built my own kernel, but there are many custom kernels popping up all the time.
Replace the window manager? To change the desktop environment, most people just install a different "launcher". That changes how the desktop, windowing, and general interface operate. If you really wanted to have the full freedom of Linux, you can install something like Debian on an android device with a dual boot setup or run it on top of android through a VNC client.
