Your reading comprehension is severely lacking. The Cowboys are celebrating their 50th ANNIVERSARY. They celebrated their 50th season LAST YEAR. Two different things.
Finding a way to celebrate the first 50 years for 2 years is just..., so... Dallas (lame). What is so significant about the an annivesary that would make one celebrate the anniversaries rather than the actual years themselves? Seriously no one celebrates their 50th weddding after 51 years of being married, except maybe Jerrah I guess. It just doesn't make sense.