7) Tablet, Computer, Portable, Phone? This applies to all operating systems in general - What do you need to use the thing for? It might not be in anyones interest to even think about Linux.
Android is Linux based. "Rooting" an android phone will give you root "super user" (sudo -su)

If you actually have a rooted phone you can see the full system folders which include ~/var, ~/usr, ~/etc and the other essential Linux directories. and Android happens to be the most used mobile OS (inb4 debate, even tho even Apple admitted it)
iOS is like Mac, UNIX (Darwin OS)
1) Its ugly - you get what you pay for - apart from Ubuntu which is pretty classy - Checked Gentoo? Its ugly - no one wants to look at ugly especially when they are used to pretty pictures.
Depends on which distro you get and how good you are at getting third-party customization. Elementary OS is fucking sexy out of the box, 30 minutes of extra work and its creamy

2) Its a mess about - Your computer probably had windows installed. Do you want to mess about for 5 hours changing this - removing that - finding out your system won't run a 64bit version of linux - hassle / worth it? I dunno you have to look at all the angles.
This is true however, this year, there are tons of new laptops and desktops by HP and various other companies shipping with Ubuntu 12.04 and 13.x already installed and ready to run out of the box.
5) Good for geeks not for 95 percent of others - Its good for geeks who know how to fix it and set it up. You try getting your mum to set up linux...
My mom, sister, and her boyfriend are all running on Ubuntu.
8) Comfort zone - Unfortunately many people usually keep with what they know - and unless forced (windows 8 lol) prefer to keep with what they know and what they're happy with. If people change the start menu and can't find what they need any more - thats the only time they'll look for different options. If they know where things are and are able to get where they need to get to. The big change might be for nothing.
This is the unfortunate part, and for those with little to no "geek" inside of them. Adapting to a Linux operating system is a challenge.
4) Its got no professional tools - Lets face it - if you need expensive tools like for example - A white board program for teaching kids - are you going to mess about and try to vmware it just so they can use it? I think not.
Take a look now, thanks to Ubuntu's incentive recently to drive linux into Education there is a lot of new applications created for professional settings. Tbh, using Wine and PlayOnLinux isn't that hard to get setup and running. I was able to install GTA:SA with no editing of anything, I installed Wine and ran the installers.
10) Open source - its good and its bad but it also can be ugly. - Some people like paying for things to know that they're getting what they're paying for. Open source might be good in that many people can work on it - but it can also be bad in that they can also exploit it. Whats to say Ubuntu goes for on sale for $10 - all of a sudden those angry free bee guys are going to have a hard time with that. Say hello to mass viruses. Its only because its free mostly, and not that well known does it not attract as much attention as windows does.
Open source is an advantage, you might be under the impression that anyone can make changes and push them. However there is an official team that must approve and changes made by the "community" and they are very strict. A major advantage of this like you said exploits, but not the way you think. You'll find exploits are fixed a lot quicker than on Mac and Windows since more people can see the code and point out the exploits to the developers.
10) Personal preference - Low budget system for the best performance? Use Linux. Max budget? Get a mac pro. (up to $5000) Medium budget or gamer ? get a windows machine. ($500 up to $1500, unless you wanna go crazy before the new chipsets come out in say 1 day later).
I have a high performance machine and use Elementary OS now most of the time. I switch only to windows to do my school work since its easier (familiarity), and to play more hardcore games like ArmA 3, DayZ, etc. Its a shame windows can't support all of them yet otherwise I might just delete windows and use only Linux.
You are missing how dependable it is for servers, considering that Microsoft uses it for a majority of their systems. Their entire cloud (Windows Azure) is powered by Ubuntu Cloud and their download web-servers use Ubuntu Server. I think this basically speaks for itself
