Dropbox seems to have two major value propositions: ease of use, and multiplatform. If you just use it on desktops, there are already several far superior options. "Ease of use" isn't sticky.

The big challenge is mobile. Dropbox's main stickiness is when developers adopt the Dropbox API, particularly on mobile. If you just use Apple for mobile, iCloud is in some ways superior (although has Dropbox's same horrible security). There's no one doing a better job than Dropbox of crossplatform on lame devices like iOS and Android in addition to desktops (and game systems, etc.).

(I admit I'm pretty biased against Dropbox because they both lied blatantly and horribly about security for a long time, and then, when caught, did a minimal job of just handwaving and continuing as before. They make file security markedly worse for users than it was before Dropbox.)

I don't think "dropbox for teams" is much stickiness; I don't know of anyone using it in serious deployments, and in a serious deployment, switching wouldn't be that hard, either.