How (and how much) are these spammers profiting? I'd expect that with time the cost/risk would increase as governments and infrastructure providers intervene a

How (and how much) are these spammers profiting? I'd expect that with time the cost/risk would increase as governments and infrastructure providers intervene and the reward would decrease and people wise up to spam/scams. But the problem just keeps getting worse. Is the decreasing in technological cost/difficulty just out-pacing the decreasing ROI?