G+ was a significant effort that was abandoned.

I'd personally define that as Google hedging their bet's and being prepared in case they needed to truly pivot, and then giving up when it became clear that they wouldn't need to. Sort of like "Apple Intelligence" but committing to the bit, and actually building something that was novel, and useful to some people, who were disappointed when it went away.

Stadia was always clearly unimportant to Google, and I say that as a Stadia owner (who got to play some games, and then got refunds.) As was well reported at the time, closing it was immaterial to their financials. Just because spending hundreds of millions of dollars or even a few billion dollars is significant to you or I doesn't mean that this was ever part of their core business.

Regardless, the overall sentimentality on HN about Google Reader and endless other indisputably small projects says more about the lack of strategic focus from people here, than it says anything about Alphabet.