Thinking about it as "Google failing", as if Google is in practice a single entity that can be failing or not at its UI/UX, is probably the wrong way to think about it. Google is built up of many, many teams - some of them will prioritize UI/UX, some won't, some will be good at it, some won't, etc.

Of course there is some amount of influence that the culture and internal processes of Google exert on its product teams, and I'd argue that it was never really that good at UI to begin with. But I still think it's usually a bad idea to think of a company as a whole, because people will start playing the "but look at this product's UI" game, which isn't very productive.