This only makes sense, considering upgrading to the latest O/S on a Mac is generally less than $30 and in the case of Mavericks, it was free, so yes, upgrading is a no-brainer to those using a Mac. Windows users are still using XP only because they hear the horror stories of the next O/S, in that case, Vista which was terrible for upgrading, quite simply because the Vista O/S required so much more memory (RAM) and to a Windows XP user, that had 256mb or maybe 512mb, they required a minimum of 2GB and preferably 4GB of memory. This is generally never the problem with the Mac O/S when it comes to upgrades.
http://feedly.com/e/nT8eeBkC