Most likely because extremely low number of people (by Google's definition) would use it and there are other things to prioritize. For a feature to be interest

Most likely because extremely low number of people (by Google's definition) would use it and there are other things to prioritize. For a feature to be interesting to just 1% of Google users, it would need to appeal to 35 million users and this is unlikely. Even if it did, features that touch 1% users rarely get to the top of queue (unless those 1% users are "whales").