Most of the people posting "(Insert Console name here) is doomed!" threads are nothing more than a bunch of procrastinators avoiding their responsibilities by trying to stir shit up on a forum. They're like Freddy Kruger in the Dream Warriors - if you give them attention, you give them power. When they find that no one is responding to their ignorant posts, then they will be defeated.
So, just ignore them, don't post replies on their threads. They are a silent voice in the industry that goes unnoticed and unheard.