Don't forget prisons and police as part of the cost.
I actually don't fear the power cost/difficulty = bust .
I do fear lack of demand due to public's perceptions of BTC = low price = bust out.
Police and prisons exist for a variety of reason. Direct cash theft is probably small potato's compared to drugs, assault, and homicide. So far I have seen nothing to suggest that Bitcoin eliminates financial crimes in general. It will certainly change the nature of some, but we've seen Ponzi schemes operate just fine within the Bitcoin realm.
In terms of acceptance, right now Bitcoin is a "solution in search of a problem". I have yet to see a compelling reason to use Bitcoin instead of USD for anything so far (yes I am a USA resident). The very few times I've purchased something with BTC, it was mining related, and required by the Seller. Just my $.02 on Bitcoin acceptance.