Sales is tough - there are a gazillion components you need to master to be really good at it. Because it's driven by feelings and emotions more than anything else, you need to understand how to connect with people and guide them through the decision making process.
There aren't many "sales" college degrees out there, and most salespeople haven't had much specific training. But there are definitely strategies that work - and don't work. It takes a lot of time, effort and know-how to become a sales guru.
That's why sales training is critical for successful sales teams. However, most sales training focuses on what to do once a prospect is engaged. That's great, but I was in sales for over 12 years, cold calling and knocking on doors, and the biggest struggle I had was actually getting an appointment. And it's even harder to get appointments now than it was back then.
Knowing what to do once you get a meeting with a prospect is important, but it doesn't do you any good if you're spinning your wheels trying to get the appointment in the first place!