I don't know all the history here, but my understanding is that Chrome's engine was never offered in that same sort of way. It was just part of the chromium project, apparently a part that increased the difficulty of integrating with WebKit, not an api intended to be taken by others and integrated into their browser.
It also means that the work they do on the rendering engine for Blink won't be constrained by the constraints imposed by support the various WebKit implementations.
Why is it sad for Chrome development not to be held back by WebKit when each project prefers a different approach?
Personally, I think its win-win: Chrome and WebKit, which have conflicting approaches to a variety of different issues, are free to take their own approaches and prove them. This is a good thing for progress.
> It's certainly not the argument that was made in this blog post, but it certainly is a believable one.
Its actually exactly what the post says when it says "However, Chromium uses a different multi-process architecture than other WebKit-based browsers, and supporting multiple architectures over the years has led to increasing complexity for both the WebKit and Chromium projects. This has slowed down the collective pace of innovation - so today, we are introducing Blink, a new open source rendering engine based on WebKit."
Forking happens all the time and is natural: good since you can go your own way, bad since you no longer contribute to the mainline. Its like speciation in that way, where some group of animals splits off and stops mating with (and hence evolving with) another group of animals.
Blink is open source, it's simply a fork of WebKit. That's why Opera is intending to use it instead of WebKit2. It's like Google wanted to take their ball to another court and still let everyone play.
That's in theory. In practice nobody bothered besides Apple.