Not trying to be facetious or anything, but honestly I wonder why at this point anybody would bother using any Google product besides the triumvirate of Search/Maps/Gmail. What's the point?
While you're not being "facetious" you're being "glib". Inbox was obviously a place the gmail team used for experimentation and now they are folding it back in. Besides you're making it sound like there was some huge cost involved in adopting or in abandoning Inbox, which there isn't.
HN is for curious humans to exchange thoughts in community. It's hard to imagine anything that undermines curiosity or community worse than this. We frequently ask users not to accuse each other of astroturfing or shilling without evidence, but when we do find evidence—and there's a lot of it in this case—we come down hard pretty quickly.