All they have to do is make it hard enough that it takes 6 months to unlock it and they've effectively won. Because those users who generally want superuser status over their phones only have them for about that long before the 'next best thing' comes out and they switch over to it. So sooner or later guys like Birdman won't even bother, and/or it won't matter if they do because once a device is rooted the rooted crowd will have flocked to some other device.
Perhaps the X, Dinc, Nexus and EVO will be the last of a dying breed of rootable phones.