I don't doubt the existing code was a mess, but I'm pretty sure their time would have been better spent refactoring it into a more modular structure. For exampl

I don't doubt the existing code was a mess, but I'm pretty sure their time would have been better spent refactoring it into a more modular structure. For example, what actually made people switch to Firefox eventually was tabs and a popup-blocker. There was no need to rewrite the entire network stack from scratch to support this.