Earlier quoted context omitted.
I don't see Google Plus as hubris. I just think they saw a threat in Facebook and felt they had to try and build a competing product (and happened to have the time/money to invest). Doing nothing while a competitor gains steam would've been hubris.
My read on the whole Google Plus thing was that they drastically underestimated the difficulty of convincing people to actually use it. They clearly had the expertise to build it, and they had some interesting ideas with their circles of friends or whatever they called them (though I think they missed the mark on how they used them). But they couldn’t convince anyone to actually use it. Maybe I’m wrong and internally…
I think you're wrong with probably the same confidence you think you're not wrong. :)
At most, I'd say they didn't expect it to be as hard as it proved to be.
I totally agree that Google just didn't get it right, but all the things you describe, to me, fall under a mix of "they had to try", and "it was working for Facebook" (but also having to differentiate from Facebook at the same time, eg with circles).
(Disclaimer, I guess) I was working for Facebook when the whole Google Plus thing happened, and Facebook definitely saw it as a serious threat. I don't at all recall Facebook folks laughing it off as Google hubris, more like it was a long shot, but Google wasn't to be ignored.
Upvote for you regardless, because I think it's a solid take and an engaging comment.