Not one person around here said in the off-season that we needed a DMF because the current three might all get injured at the same time. Can't really say it's no surprise, because it is surprising!
To have two players in the same position injured in one game is always rare. Particularly when the guy ahead of them is already injured.
We all just wanted an improvement in quality at DMF, nothing to do with injuries/numbers at all - we wanted Flamini out and a shiny new guy in.
Arteta and his injuries still would have been here, and we'd still be in this exact same position - unless we had a crystal ball so that we knew the new guy wouldn't get injured, ever.