I don't take it as scaremongering, but I'd add that the switch cost from drive to dropbox is pretty low. Google will announce if it's going to close drive, and in the meantime you're paying some fractional percent of what dropbox charges.

If google shutters it, it's not like copying a bunch of files from one place to another and waiting for it to auto-sync is a difficult endeavor.

(right now my money is on Yahoo! acquiring db to better compete with Google...but the price might be too high).