And then you just drop them for a competitor. Since you have no sunk costs, you lose nothing by hopping to whatever the best option is other than a small amount of pain migrating, But for something like dropbox, there isn't that much lock in.
I've never heard of OnePass so I have no idea, but Dropbox is very easy to replace. I'm also not even sure how you'd expect a "pay once" model to work for cloud storage.
