Well it’s so common Wikipedia has a dedicated category for them: https://en.wikipedia.org/wiki/Category:Discontinued_Google_a...
Im not disputing that Google does this, but ever since Google Reader was stopped this has become a stock comment on basically every HN discussion on Google products (other than search & ads) and has long ceased to have any value at all, and seems to be just accepted as some gospel without any evidence that this is a bigger problem with Google than the other tech giants.
I don't think hk__2 is promoting another big corporation.
Perhaps it's HN apophenia but Google's record of discontinuance does not seem insignificant - it is valid for anyone to be skeptical of their ability to maintain any newer product in the medium term.
That said, I think anyone who's followed Firebase closely since the acquisition should have reasons to have more confidence in their commitment in this one particular case.
I like it so much that I even found a old copy to install on windows 10. 6 years after it is discontinue and still much more useful and much faster than windows 10's search bar.