Because then the very next bounty would have to be, to replace NetSurf.
Rob's project is really the way to go, WebKit, Safari, et al, are lightyears ahead of NetSurf, so why even mention it?
edit: sorry, I just realized you asked, not to port NetSurf, but why not start from Scratch...well really that would be up to Rob to talk about, but I would have to imagine, because its faster to do a port than to 'reinvent the wheel' so to speak..i.e start from scratch.
