I don't know if Dropbox has a limit on file size, but whether or not they can do that, it's not their positioning. They're all about "sharing files", but to say

I don't know if Dropbox has a limit on file size, but whether or not they can do that, it's not their positioning. They're all about "sharing files", but to say "we let you share big files!" would be too narrow, and turn off or confuse more people than it would attract.