Also forked from something Apple made (Webkit)
The fact that basically all of the big companies (Microsoft, Google, Apple) use Webkit or Chromium shows that it's very difficult to build and maintain one successfully IMO. I think that Mozilla are essentially the only ones developing something that's somewhat competitive, not to mention that most smaller companies (e.g. Opera, Brave, Vivaldi, Island etc.) all use Chromium.
I'm not saying that it's easy to succeed with a product even after you've bought it, or started it from a fork (see less successful Chromium/Webkit forks). I'm just saying that it was not something built from the ground-up in Google. For example, v8 was and really changed a lot of things in the JavaScript world including Node, Deno etc.
The graphics libraries are definitely more custom... Although in total fairness they're not entirely ground-up Apple either; Quartz was based on Display PostScript, which was acquired from NeXT, and which NeXT built in collaboration with Adobe based on Adobe's earlier work on PostScript. It's obviously true Apple's done a lot of work since then (e.g. Metal), but in that case, so has Google since forking Webkit.
It's turned out that vector images aren't that performant or easy to deal with for various reasons, although they are still used in some places.
I think you missed the point, there's two forks in the history of Blink (Chromium). Yes, Blink is a fork of WebKit, but WebKit is a fork of KHTML. So it's not like it originated at Apple either, it originated at KDE.
I've already stated that Chrome's success is not just because that it was forked from Webkit (e.g. v8, and other things that people mentioned here as well), but it was a huge jumpstart for them, and it would've taken them much longer to get a leading browser without it. e.g. Microsoft basically gave up on developing their own engine after failing with IE and the original Edge - and are now also based on Chromium.
Chrome is (IMO) much better than Safari, Maps is (IMO) a great product, Youtube is a a huge success and much bigger than it was when they bought it (homegrown Google Video failed), Android was also essentially an acquihire, as others have mentioned (using a lot of Google's resources) and is hugely successful. It doesn't change the fact that most existing Google products today are acquisitions that they improved, and not home-grown products from the "20% do your own thing" era - which is what the original comment talked about.
1. The V8 JavaScript engine, which blew away everything else. 2. The sandboxed, multiprocess, threading model.
Those were the two things emphasized in the original Chrome "comic" at launch, if I recall:
Firefox only declared it completed electrolysis in 2018, nearly a decade after this comic.