Spam works because it pays. Whether through phishing, selling lists, or otherwise, spammers make money. Sure, some do it just for kicks too. The real problem is that spam makes life more expensive for everyone. Legitimate bulk emailers (e.g. the number of order confirmations that a large e-commerce site sends out in a day could be considered "bulk") already spend time and capital to ensure delivery – this cost is already passed on to customers in one form or another (directly via service fees or indirectly via seller charges, passed through into pricing/margins).
An analogy can be found in fuel surcharges – at FedEx, UPS, Waste Management, and other businesses. There’s a cost to doing business borne of factors in the operating environment over which neither the buyer nor the seller may have direct control – but someone’s gotta pay.
Look for pass-through email postage costs to creep into commercial messaging situations first. And look for smart companies to explore [secure]RSS as an alternative messaging solution.