(Disclaimer: no special knowledge of Google, all below is solely my opinion and not to be considered as factual.)

Google's revenue model is and has always been web first. The more business happening on the web, the better it is for Google writ large, especially back when competing with Microsoft was a larger priority in that space.

It's much harder to pirate a web app, for obvious reasons, than a desktop app. Desktop apps being easy to pirate shifts professional software developers on the margin towards more web apps, which means more commercial activity centered on the web, which is is good for Google. So one could imagine pretty good business reasons to be at least blasé on the topic.