I agree with you.
But any shared mailbox format that makes assumptions on the type of locking used by other accessors, and does not provide a standard locking mechanism bundled with the format specification, is b0rken. But nobody ever claimed that mbox was anything else, did they? ;) mbox is yesterday's format, and the only reason people cling to it is for convenience and "if it works, don't fix it".
Actually, there are a number of reasons why I still have mbox format. Most of them are legacy. But keep in mind this is 10yrs of legacy in the same format. That kind of inertia takes effort to break free of and in some cases there are political situations which make breaking free just about impossible. But thanks for only attributing laziness to those of us who need to use mbox.
The reason I want an imap and pop server than can handle both mbox and maildir is so I can gradually migrate my users over.
I can take them in batches and move their mail spools to maildir w/o massively disrupting their normal activities.
200-400 users at 2-4 a day will take me 1/3 of a year.
Doing them all in one day will take me a lifetime of cleaning up problems and also trying to explain to those above me why I put all of our users through it.
Nobody with their wits intact would come up with something as pathetic as the mbox storage format in 2003. That's _my_ personal opinion on this matter.
We're not disputing that. But mbox is going to HAVE to be there for migration, otherwise you'll not be able to get the users moved over.
-sv