You're also mixing different traditions here, that all have their own perspectives on what monks can and can't do.

Materialism in the Buddhist sense is about mental attachment. Desire (attachment) stems from the mind, not the object itself (attachment is not a property of the object), and different meditation practices have different techniques to work with that mental attachment. Reducing your possessions is a very effective strategy in reducing attachment--but it certainly doesn't do anything without developing mental renunciation simultaneously. I'm curious if this is an American or Western perspective on poverty--that poverty itself is somehow liberating.

In terms of email, there's nothing luddite about Tibetan Buddhism. Technology is embraced as another avenue for speech, which the mind can be attentive to.