There are probably many reasons. They don't have the time. They don't like writing. They don't get an immediate response from prospects. The point is, had they been persistent and kept on mailing their newsletters month after month, year after year, I am convinced that these folks would have won big.
Repetition is the key to getting results.
TV commercials and print ads don't run once. As you know all too well, they are repeated over and over again. Big advertisers understand that we are bombarded by messages all the time and that the only way to cut through the clutter is to be there often. That's why you need to be persistent and keep your message in front of your target audience on a regular basis. If you're using postal direct mail, don't call it quits after the first mailing.