The problem with saying "Webkit is the new IE" is that IE was allowed to stagnate because it was a singular browser with a dominate position in the market. When that position was achieved, it was no longer necessary for the company maintaining it to continue to compete.

Webkit, in contrast, isn't controlled by any one company. The people using it have access to the source, and more often that not are contributing to the project themselves.

I don't think the competition is going to end, It's just going to change form.