Google pushed a new version of its Text-to-Speech app a few days ago, and it actually removed a feature. Updates usually add new things, so what's the deal? You can no longer download the high-quality voice models on your device. However, Google has updated the changelog to explain that you don't need them anymore. The regular voice is even better now.
According to Google, the "standard quality voices now surpass the quality of the high quality voices." Therefore, there was no reason to keep the high-quality ones in the app. It wasn't a very good experience anyway. Most users would never find the menu to download additional voice models. Even if they did, the downloads were north of 200MB. The standard voice is about 3-5% of that size.
There seems to be some question whether or not the standard voice is as pleasant, but the decision is made one way or the other. This update also added Hindi and Indonesian support.