I agree, but surely the way that Linux (and Android) is made makes it inherently more secure? Without root access there's not much that can be done to truly compromise a Linux system, and Android sandboxes everything
I agree there's a certain degree of additional security provided by sandboxing, but we've already seen APKs (e.g. Z4Root) that can gain root access, so it's not infallible. It is one of the reasons that I use Chrome on all platforms - if you check out Pwn2Own, Chrome has yet to fail, and that it mostly due to sandboxing - however, it is not a panacea!
There is definitely an element of "security through obscurity" around non-Windows OS's. Note the use of the word "element" - I'm not saying that Linux or any other OS are insecure, just that they are attacked less than Windows.
The point is that modern Windows is far more secure than most people realise - any OS given the same amount of attention by the "bad guys" in comparison to others. Vulnerabilities exist in all OS's and will continue to found and exploited.
I'm in full agreement that currently the real security threats on Android are down to users not paying enough attention to the permissions that an app requests when it is installed, but this will likely change as Android gains popularity.
I do pay attention to the apps I install, so I personally don't feel the need for any kind of security suite on Android at present.
Regards,
Dave