I was surprised to find that this isn't among Gwern's 10 Google services most likely to be shut down[0], but I think it may just be too recent to have been included; I don't know that he's ever re-run the analysis.
Hangouts was launched 4 November 2013, so it came after I finished it. I did ad it to my followup list for the 2018 update when I evaluate the predictions and update the data to take a second look at the model results, but the followup list is stashed as a comment in the page source so unsurprisingly you didn't see it.
[0] http://www.gwern.net/Google%20shutdowns#predictions