Efficient my ass

I suck at investing.  I'm really bad at it.  Nonetheless, one thing I'm seeing which makes no sense whatsoever is the price of oil.  I'm reading a bunch of articles talking about how oil is going to remain at a $50 price point for the foreseeable future, down from it's $115 high in 2014. WTF!  Think about that for a second.  ONE year ago the price was $115 and now it's less than half of that and nobody saw it coming.  Really?  How on earth could people predict that it will stay at $50 when just one year ago the smart money was pricing it at more than double.  It's not like oil is a new commodity nor a hidden one.  How could people have been so wrong then and be so assured that they are so right now.  It doesn't make any sense.