You are aware that the average user will not be able to perform the Linux part. So you must use the GUI. Enter the root password (The what now?) and then click on OK and so on.Installing something like Google Earth gives me errors when I try to do it.(Yes, I know how to solve it) No such issue on Windows.
Back in the early 1980's I use to teach clerical staff how to use Unix workstations. Not one person I taught had any issue with using the command line or the GUI for that matter. Fast forward to 2015 and people seem to have developed a mind block to using the command line, I wonder why? Have people really got dumber with regard to using computers?
Ok I will give you a Fedora 21 with a KDE GUI example.
1. Select your application launcher (for people with MS Windows that is equivalent to start and FYI Unix/Linux had it first)
2. Select "Applications".
3. Select "Administration" then "Software Management".
2. Select "Computer"
3. Select "System Settings" then "Software Management"
In the "Software Management" GUI search for the software you want or just browse the repository. When you find what you want just install it and all dependences are found and installed for you. Of course you do need system admin privilege to do this.
The main difference is that for most of the software finding it is easier on Linux. Still there are applications that are not in the repo and at that moment Windows is easier.
I do agree with what you said here but isn't this article about trusting the site were you want to get the application from. It's not that difficult getting an rpm or deb package if one exists however you really need to know how to install it and in the majority of cases you can use "yum" if using Fedora/Redhat distributions and "apt-get" is using Debian type distributions. Of course the best and safest way is to use the command line for the install in this case however IMHO if people feel that their brains will explode I strongly suggest MS Windows and slowly back away. :)