Windows has always set the default page file size to a range of 1.5x to 3x the physical RAM size. And given that 90% of the world's OS is Windows, I think that the vast majority of operating systems don't have it set to half the RAM size. :P
That having been said, setting the paging file size based on the physical RAM size is silly and makes no sense. Even if you set it to half the RAM size, that means that on systems with more RAM, you have a larger paging file (when in fact you will be using less of the paging file). I normally set my paging file to a static size, either 1GB or 2GB, regardless of how much RAM the system has.