Going with the 13k/yr figure for bulk food, it strikes me that that is essentially pocket change compared to the various other cost involved, many of which would be the same for any creature, regardless of size, fresh out of the theoretical cloning tanks. Second and third generation ones, if we decided to keep them around, would have milk straight from mom and I assume have adapted to the modern microbes, I mean they're only tens of thousands not tens of millions of years out of date. Now that first generation or so, when the nominal food bill is just a fraction of overall costs, isn't a funding issue, people will cheerfully go to the zoo just to see it and cut checks too. But I would bet the draw of a mammoth early on would be sufficient draw to more than offset the diversion of funds. Come for the mammoth, stay for the penguins, etc, not profit for the zoo. We've already got six elephants at the Cleveland Zoo and we're not one of the big ones, and I gather our elephant exhibit brought in a lot of donations compared to normal, I'd imagine a Mammoth would too. I'd be very surprised if the funds raised off the first year of having a young mammoth or even a small herd wouldn't cover the capital to set up a good zoo habitat and the food bill for a decade or more.

I mean let's us be honest, it is a mammal, baby mammals are cute, and guilt can do wonders, 'We killed them off before, surely we mustn't do it again!' and 'please, please, don't let little Wooly die all alone of his kind, sadly neglected' and there's not a news channel or talk show that wouldn't gladly have the critter on looking adorable with the flashing 1-800-SEND-MONEY-NOW sign on the bottom of the screen. Jurassic Park aside, there's very little Frankenstein vibe about this sort of thing for people these days.