You are missing the point by focusing on Mariano Rivera, which was a freak accident. The point is that you knew what you were getting when he trotted out there. Papelbon and Kimbrel, too, to a large degree. Premium closers are worth a mid-round speculative draft pick nowadays.
And count yourself lucky. Combing waivers could have killed your WHIP and ERA.
Actually, you're missing the point, which is that over half of the closers at the beginning of he season are no longer closers now, not even 1/4th of the way into the season. Why would you pay for such a huge risk? Rivera was a freak injury, but that's the whole point: closers are getting injured at a pretty huge rate compared to other positions, and there's a much higher non-injury turnover rate added to that as well.
I can't think of any logic behind arguing that closepocalypse is proof that you SHOULD pay for a position that is statistically probable to screw you over.