Comment by bunderbunder

I don't remember other browsers running less well than IE just because it was built into the OS. If anything, I've always remembered 3rd party browsers running quite a bit better.

Not certain if Ubuntu has a browser built in, but I would say that in this day and age, if GTK+ doesn't have any native components for rendering HTML then that would really stand out. It's considered an essential feature on every other platform's GUI toolkit. Just try removing WebKit from Android or an Apple OS, or pulling Gecko out of a Firefox phone.

The last exhibit would be Microsoft scrapping their plans to ship a version of Windows 7 that didn't include IE. (Though I imagine the rendering engine would still be needed - gotta display help files somehow, after all.) Turns out manufacturers didn't want to carry it, because nobody wants a computer that ships without a web browser anyway.