There were various other reason for following Blink and honestly the day Blink came out I would be shocked if there hadn't been meetings in every company contributing to WebKit putting together a mini-project to decide if they should follow Google. There were a lot of little pain points in the WebKit project and Google in one swoop cleaned up a ton of them. If anything I see WebKit as an example of failing to steward an open source project on the part of Apple or the community as a whole. Everyone was working on their own problems that it was hard to get movement to fix bigger problems that applied to all ports. Even very visible things like letting each port have their own build system sounded good originally, but was one of the things holding the project back. I was on the edge of the community (worked on the qtwebkit port, helped port chrome to linux, ce port, blackberry port, etc) so I know only so much, but it would be interesting to hear from someone closer in the community not about what was bad technically in the project, but how as an project we (socially?) didn't fix them. Why didn't the WebKit meetings fix this? Did Apple have too much say because they owned the svn server to the detriment of themselves?
I heard that after the fork, both sides were able to clean up and remove a ton of code (thus benefiting pretty much everyone).