Qualified software engineers, managers, marketers and salespeople in Silicon Valley can rack up dozens of high-paying, high-upside job offers any time they want, while national unemployment and underemployment is sky high.
Salesmanship is limitless. Our very living is selling. We are all salespeople.
A book tour is not a good opportunity to let your mind wander. You have to pay attention, remember salespeople's and interviewers' names, succinctly summarize your book in a 'selling' way, and so on.
I've known entrepreneurs who were not great salespeople, or didn't know how to code, or were not particularly charismatic leaders. But I don't know of any entrepreneurs who have achieved any level of success without persistence and determination.
Great salespeople are relationship builders who provide value and help their customers win.