On the other hand, if all browsers just used webkit then maybe we'd finally get "write once, run anywhere" JS, CSS, etc.
Don't forget that on mobile platforms, not including Windows Phone, WebKit is already the standard engine. Safari, Android's stock browser and Chrome all use WebKit and developing for mobile is a ghetto, especially because each version has their own quirks and bugs (and there are dozens of Android stock browser variations in active use at any given time).
WebKit can be maintained, forked etc as the world pleases.
I agree that if there is to be a rendering engine monoculture, it might as well be open source, but that in itself guarantees nothing.
Even today, mobile users typically account for only about 10% to 15% of a site's traffic, for sites that don't directly target mobile users. Mobile just isn't as important or widespread as a lot of people think it is.
Their February 2013 results are at: http://gs.statcounter.com/#mobile_vs_desktop-ww-monthly-2013...
It gives a good sense of the current situation. Mobile browser usage is under 15%. It's nothing compared to the usage of desktop browsers. The growth from 2011 and 2012 isn't even that impressive, given the all of the hype and attention surrounding mobile.
> WebKit is open source, so anyone can fork it and build
> their own version with any fixes or changes they like.
So now you have a fixed WebKit that nobody else uses.
It's about the same as when you start at a company with a large existing codebase. You're not going to get much done until you've read and understand the chunks of the code that relate to what you need to do. This spinup time is definitely bigger than the hour it can take to fix a bug in a small project that you previously had no experience with, but it's definitely within the realm of the possible.
> Imagine what will happen if there are no competitor and
> webkit core engineers do whatever they want and still
> people use their engine.