Earlier quoted context omitted.
"Installing software was a mess." Of all the things to complain about in Linux, you choose the one thing that Mac OS and Windows still don't have right, and Linux had pretty good even back then?
Installation on Windows was always much easier; all programs had a relatively consistent UI wizard that stepped you through the installation process. Installing software from disks on Windows was really convenient (and disks where the real deal back then). The fact that Linux relied on people to install stuff with the command line was a massive oversight. UIs are just way more intuitive than shell commands.
It's that there are so many different standards for installing software, overlapping in sometimes conflicting ways.