In contrast, Microsoft Word changes drastically every 3 years or so, even though it already contains more functionality than most people will ever use. Why is this the case? Perhaps MS Word changes because MS doesn't get paid unless people buy new versions of the software, so they bloat their code adding more and more features to lure customers to upgrade.
I've always been against the idea of software subscription pricing, mainly because when I buy a piece of code, I want it in my greedy little hands. I want the CD, and, if possible, the source code. However, it occurs to me that the software that I do license (mostly techno stuff like Matlab) is much more stable than the software I buy. Ditto for the free software like Emacs.
Perhaps the idea of buying software is the problem. MS has wanted for a long time to move to a subscription model, and I've always seen this as another attempt to grab more money and power. But perhaps if they were to sell software subscriptions, the MS programmers could spend their time improving the base product rather than chasing creeping featurism.