Direct marketing is relevant only when margins in the business can afford the cost of sustained contact. Cost per thousands is much higher. First we lose money but every time the losses come down. The future value and life cycle value are of much more importance. It is relationship marketing and that is where profits are.
Increased research costs are paid back in the first year or less than that by mailing less waste mail.
The attempt should be to curtail monthly mailing by eliminating wasted mail. The cost of computer processing is also dropping rapidly. It will give a further boost to direct marketing.