In the BeOS days there was a fair bit of argument (no doubt repurposed from Linux turf) analogizing the healthy necessity of biodiversity in nature and platform diversity in the computing world. This line of thought beautifully re-played in Martin Price’s recent piece on Platform Diversity.
Personally, I’m sick of hearing about keeping systems secure from so-called “security experts.” All they ever talk about is patching Windows. You never hear one suggest that it might be a good thing if we weren’t all running the same stupid software. Of course they don’t. The lack of security in Windows is their bread and butter.