There's probably oodles. Off the top of my head, there's Apple's web page for X11. Except for a spinal tap joke, the whole first section of the page was devoted to the acknowledgement that they were building on top of OSS from XFree86.
Blink? Not an exact parallel, but afaik, google clearly gave credit to webkit. And I think Apple gave credit to KHTML for Webkit (and in fact worked with the khtml team for a while).
But even if FAANG don't typically give credit to projects they fork, that doesn't mean it is ok. That's like saying all the big political parties gerrymander, so gerrymandering is ok.
Hell, can you show an example from the author's own company? That company's about page has a blurb on contributing back to open source that seems to be on par with what Amazon does to contribute to open source, and the author is sponsoring 4 people on GitHub, but where are the loud proclamations that people are clamoring for in this thread? Whose shoulders are being stood on there? Is checklyhq.com really running a SaaS offering without benefiting from many, many more people than the outward stance suggests?
This whole thing is very reminiscent of the Occupy Wall Street movement. People are very sensitive to the injustices they perceive themselves as having to endure especially in relation to those wealthier than them. But where's the willingness to jump out of local scope and apply the same principle globally (and reflexively)? It seems to be absent.
