I admit, I am 50/50 on if we have seen the final match of The Undertaker or not.  And with no formal announcement from WWE or Mark Calaway himself, the door is still open.  I honestly feel there is still a good chance Sting vs. Undertaker at Wrestlemania 31 may still happen. And here are a few reasons why....

1)  As I said, no formal retirement announcement as of yet

2) Ending the streak adds more mystery as to who would win a Sting vs. Undertaker Wrestlemania match.  If the streak was still in tact, everyone would feel Undertaker would win.  

3) I think Undertaker would want to go out on a higher note, even if he loses his last match.  It is no secret Undertaker was hurt during the match with Lesnar.  As a result, this was not one of the classic Undertaker matches as we have gotten used to at Wrestlemania.  Wrestlemania 30 being Undertaker's last match is like he went out with a little fizzle and not in a blaze of glory.  

I await other's opinions on the subject.