Flag on the field, 15 yard penalty for "magical thinking".
Would you too like to know how to write a Linux virus in 5 easy steps icebike? Its trivial and uses the exact. same. methods. that the Windows viruses use, in fact it would be quite trivial to make them cross platform! Oh but "that wouldn't work IRL" you say? Might want to tell that to the owners of all these infected Android systems. BTW please note the date of the second article, last figures I saw now had the number of infected over the million and a half mark but since I couldn't find a reliable source for those figures and didn't want anyone saying I'm picking facts I went with the older article.
Go ahead and try the first article for yourself icebike, you ARE running Linux, correct? It has step by step instructions and works just like the "KDE Look" bug that spread through the KDE community did a couple years ago. When you do and see that they infect the system just fine maybe then you'll accept that Linux security is security by obscurity and realize these companies buy windows FOR A REASON and its because you have one company to call that is in charge of the whole stack. Oh and don't bring up servers, those are stripped to the bone, have nothing running that is not absolutely required AND locked way the hell down. I can do the exact same with Windows embedded and NOT have to rewrite a couple hundred grand to a couple million in code to work on an OS that is unsupported unless I write big checks per unit to Red Hat.
Sorry icebike but no matter how you slice it? Your math don't work. if it did these banks would be happy to switch, think they have ANY loyalty to anybody but their own bottom lines? But just as al the retailers large and small refuse to carry your brand in house because they have found it wanting so too has the financial sector tried your OS and with the exception of a few server roles its been passed on.