Because that’s how that movie had to end. And that’s why i didn’t like how i met your mothers’ later seasons. It should’ve ended with ted shooting himself in his apartment because he fucked up. Life gave him chocolate boy good looks, scores of beautiful women but he fucked up. And watching his brains splattered all over his empty apartment would’ve made barney realize the error of his ways and propose to robin right there. That would’ve made sense. The existence of unicorns makes more sense than the ending they shoved upon us. Bastards.