I used to think similar to you, as an engineer I didn't see value in sales. Then I tried to sell something myself and I realized it is not easy. You hear no all day long it starts to get to you.

The best sales people I've seen are relationship builders. They understand their clients needs (Even if outside the core market) and try to find a solution for their needs. This looks like wining/dining on the outside but it's important.

I would suggestion anyone that wants to build something to try and sell first. Then you'll realize why they get paid and can be very valuable.