That's an interesting way of looking at it. Apple no longer get a free ride. On the other hand, now that Firefox is using WebKit perhaps Mozilla just replaces Google there.
> On the other hand, now that Firefox is using WebKit
Firefox is still using Gecko, and is working with Samsung on a long term effort to develop a new engine (Servo) in Rust.
You may be thinking of the recent news that Opera is using WebKit, but even when that was first report it was identified that they were really basing on Chromium rather than WebKit proper, and they've announced (in this thread, even) that with Chromium moving to Blink, Opera is following.
Sorry I should've been clearer. I am aware of that, but since anyone can use the code, the most important thing for those using it is that what they have tired their product to is actively maintained. If they don't do the majority of the work to maintain it then I think of them as getting a free ride from whoever is actively maintaining it. I don't mean that as a negative, either. Every company gets free rides in some way or another. Web companies off those that pioneered the web, for example.
KDE originally built KHTML. WebKit however is mostly a product of Apple. They made it into the product it is today. Along with help from Google/RIM/etc. But it was mostly them since they needed it to work in Safari and iOS.