Do you have to earn online?

I have taught, face to face, five people who are now making at least €2,000 ($2,895) per week providing a valuable service to small, local businesses. None of these people have ever sold anything before and had no idea about building web sites or how a business could be made more profitable. Each person works less than three hours a day BUT IT IS WORK! They do face to face presentations and calculate the immediate cash savings that they can guarantee to their clients while exposing them to the risk of finding more cash customers.

Since losing most of my sight I have offered my training through a 15,000 word ebook to internet marketers on sites like the Warrior Forum. All the IMers who put my training to use made money - even the slowest of them only took three days to earn $250. Strangely, not all tried my methodology and none that did have continued to use what they learned from me, the general reason being that "it isn't really internet marketing".

What is it that makes them unwilling to use a proven money making method - one which five non-internet marketers are using to make over €100,000 per year? 
Simple, stupid question - If you are an internet marketer, do you have to earn online?