Please do not misguide people. Most of the points you mention in disadvantages are not valid.
Point 3: For most popular computers (Dell, HP etc) networks are hardly a problem. Ubuntu supports ethernet LAN by default and during installation, one can check the option to install wifi drivers. Wifi runs fine especially with Broadcom wireless hardware, which are quite popular.
Point 5: Ubuntu (and other Debian-based OSs) have LOTS of software available. It would be hard to find an area for which software are NOT available in linux.
Point 6: Again, all you need to do is check a box during installation to have codecs for most audio/video formats, including mp3.
Point 7: Perhaps they’ll take time to answer an new question. But Ubuntu has been in use for long enough that most of your concers will already have been answered. All you need to do is a google search.
Point 8: Ubuntu installation is VERY EASY. In fact, according to many people it’s easier than installing Windows. I, for one, just booted from an Ubuntu disc and installed it without needing to ask anyone anything, even the first time.
Point 9: Decently good drivers are available for most graphics and audio devices. Specialized hardware, and some printers may have problems, that’s all.
Point 10: (a) The default Ubuntu user interface (Unity) is actually quite intuitive to those who have not seen the earlier interface (Gnome 2). (b) If you really don’t like it, you can just change the interface and install any of the others (Gnome 3, Mate, KDE, Cinnamon…)
You are only right about games, to some extent. There are a few good games for Linux systems (also known as GNU/Linux systems) as well.