Microsoft makes a lot more money on Windows than Apple does on OS X, so they spend more money improving it. A lot of that money comes from corporations with expensive, legacy software, so Microsoft has to maintain backward compatibility. That's a lot of extra work that Apple doesn't usually seem bothered to do.
Slimming an OS down as it gets older is also not something that's done quickly or cheaply. I also noticed that OS X became more and more bloated since Lion. Mavericks was the last really usable version to me, although I always did have to install a bunch of third-party tools to get the UI to behave in an efficient way.
I think you're totally right, but there are some people who have an almost religious, fact-free hatred of all Windows versions. I don't see too many OS X fanboy posts anymore, though.
