Cause google is switching their primary search to mobile instead of desktop. It's time for N4G to change, this isn't 2010 anymore.
People are scared of changed. The new design is way better functionality wise and cleaner. Time for change, people will get use to it. Only complaint, when you type in the comment box, it keeps extending down per character type on the desktop version.
Sorry but last version was horrible. This beta is a welcome addition.