Nothing, of course. They sat in their offices, had lunch, drank a lot and waited for people to come to them. Then he studied how most sales people worked. He compared this with IBM, then the world's best selling organisation. The average IBM salesman did it exactly the other way round.
Nobody likes cold canvassing.
And you don't have to if you know just how powerful a good sales letter can be - and what it takes to create one. Most people write bad letters because they don't take them seriously. They write letters every day in business, so they think any fool can write a sales letter. Consequently, many do. Good letters are hard work.