What exactly does dropbox offer that apple's iCloud won't bring to the table? (not to criticize dropbox, but it would seem relatively easy for apple to replicate)
There certainly is a Dropbox shaped hole in iCloud. (I will not dare and claim that there is an iCloud shaped hole in Dropbox. iCloud didn’t even have a chance to be successful yet and Dropbox is very successful without anything iCloud offers.)
Now, I have been thinking that Apple’s long term plan is to get rid of the file system (as something the user has to deal with). iCloud and even more so iOS are steps in that direction. Even Apple, however, has to acknowledge that there will at least be a transitional period between now and that future. That’s where the Dropbox shaped hole comes in. Dropbox is (currently) all about the filesystem: There is this folder and you can stick anything at all in it to get it synced across your devices and to be able to access it from the web.
Dropbox has that implemented perfectly. I don’t know whether Apple could copy that. I personally never used it but people have been telling me that iDisk (which was conceptually pretty similar to Dropbox) sucked.
Still, it would be weird for Apple to go off in a direction like that. Not sure whether they are willing to, well, more or less backtrack with iCloud (back to the filesystem).