Most of what you say is true but
* servers may be available in vast numbers, they're hardly ever run/maintained by mom I'm betting most MS-servers live a virus-free life too.
* malware writers are used to writing malware for windows. Why throw away all that knowledge and experience and start over from scratch on another platform ?
* there IS plenty of malware out there for Andriod... you'll probably prefer to call them trojans and dismiss them as 'not real virusses' because they simply use the user as the attack vector (swipe here for free ponies!) and don't really do that much harm except for stealing user info etc... but hey, let's rather bring up SASSER again, after all it's only 9 years ago windows got hit by that one!
I somehow don't get why people always need come up with the 'you need to run as administrator on windows' argument. You don't need to, maybe a lot of people do, but you don't need to. Ever since the introduction of the UAC I see little difference between me running Win7 or me running Ubuntu; except that the UAC is quite a bit more user-friendly. In fact, after having to type my password for the umptieth time so I can change an ini file hoping to finally get my display at full resolution (old laptop) I started running Linux in 'administrator' mode.
Get with the times and stop bashing Windows with old arguments. I don't like Microsoft because of the way they run their business, but that doesn't make (all) their products bad. Let people simply use what they like and quit these 'religious arguments' about what OS is superior. If the OS lets you run all the software you /need/, then what is the problem ? You like Ubuntu & Gimp, fine. She likes OSX & PaintShop, fine. I like Windows and Paint, so leave me alone.
(And don't come whining about how for every program on Windows there is a viable alternative on Linux. There isn't, and besides, for every program on Linux there is a viable alternative on Windows too and yes, often it's free too... although it might not be 'open', but that's true on Android too and I not heard people asking for the source of Angry Birds yet.)