While it is a noble effort to try and push people in the direction of Open Source operating systems, the reason they are interested in inkscape is not in-line with switching operating systems. Even if it were trouble-free to do so (and currently it isn't), it would be dissasterous for Inkscape's popularity to suddenly stop supporting the more popular operating systems.
There are some companies who are currently trying to increase the popularity of Linux as a desktop OS, but they are still very far away from producing usable desktop OEM distributions that are commercially available. The reason Windows OS and Mac OS are so popular is because they come pre-installed on the computer, turning a computer into a consumer appliance. This problem is the main hurdle to wide-spread adoption of Open Source operating systems, and unfortunately there is nothing at all that we can do about it on an application-level.
If you want to fundraise for Inkscape, why not kickstarter the next development cycle like Krita does? They've been doing very well lately without pester-boxes in the application.
-C