Quote:

  "Now some people think that the cloud is
  just a hard disk in the sky. You take a
  bunch of stuff and you put it in your
  Dropbox or your iDisk or whatever, and
  then it transfers it up into the cloud
  and it stores it, and then you drag
  whatever you want back out on your other
  devices. We think it's way more than
  that -- and we call it iCloud."

All Steve is saying is he thinks they have a better idea for how the cloud should work. I don't see anything remotely similar to "vowing to kill" any particular service. I think his quote misunderstands the beautiful simplicity of Dropbox, but that's about it.

Most charitably, you could argue that when Steve has previously said words to the effect of "we think we've done something better," entire industries were occasionally upturned. For the CEO of Dropbox, to hear that phraseology used in their direction, I can imagine how they might interpret it that way.