Given the prevalence of P2P meth and apparent inability of governments to do anything about it, this does not seem like a rational position to me. If there was any reason to believe that large scale production will ever be substantially curbed, there might be a case for it.
Yes, P2p meth is rampant and cheap. However I look at it like this: Meth addicts will absolutely decide to become chefs if the ingredients are readily available, even if there's a McDonalds down the street. You're approaching this rationally, which is not what meth addicts are going to do.