> Even if I get a tarball on OSX I can double click on it and then drag the application into the "Applications" directory or run the installer.

All without opening or requiring the user to open a hideous terminal just to run the app.

> I'm not sure why this is so challenging on Linux.

Desktop Linux fundamentally can never solve this problem. All of the packaging alternatives of alternatives have created a mess and confusion around which distro can open what and not only these alternatives even work out of the box, there is no guarantee that all Linux distros will be supported for that.

At most it is a 'solution' creating a new problem; whist still looking for a problem to solve.