Is the money in the list?

Within the Internet marketing industry, there's a popular saying: “The money’s in the list.” This means the people who are making “the big bucks” are making it from their email list, not from their product launches. Is it true? If we only look at the math, it would seem to indicate it might be true. In the marketing circles where I hang out, a marketer can typically make between $2 and $3 a month for every person on their email list. As an example, let's say they sell a product for $27 and give a 75% commission to the affiliates. They are making, on sales from affiliates, a gross profit of $6.75 per sale. Of course, they have payment processor fees, etc. to also take from that, but we’ll use the $6.75 figure for our purposes here. The buyer gets put on an email list, if the launch is set up properly. The product creator earned $6.75 for the initial purchase. If the marketer is of average ability, the marketer will make between $2 and $3 a month from that customer from that point on, as long as they stay on the marketer's email list. It will only take 3 - 4 months before the profit from the email list surpasses the profit from the initial sale. Even if a customer stays on their list for only 12 months, the total earnings for the marketer will be $6.75 from the initial sale, and an additional $24 to $36 from email marketing. So, it would seem the math supports the statement, “The money’s in the list.” Is it really true?...