Not only would he be going against his word - while the internal metrics of the company are going strong - but he would be killing an asset and destroying shareholder value.
Even Zuck isn't crazy enough to pay $1B for a growing company and just kill it. That would be totally irrational.
I suspect this may very well be the best tech acquisition since Google bought YouTube.
Good luck for both of them - even though I am wary of FB's growing clout and I don't use Instagram, it's nice to see a good service find a good home that can support it over the long term.
I am SOOOO happy that Google bought YouTube. Can you imagine a world without YouTube?
I sure can't. Not a good world anyway.