I don't understand this at all. The first 18 years of my career I never saw any boundaries between those who spoke to customers and designed the software and those who wrot it and I those who tested it. It was always encouraged to fill all those rolls. People who were good at the why got helped up to speed on c++ and the stock programmers got a crash course in domain knowledge an a refresher on the bits of relevant math. Only in the last couple year have I started meeting programmer that didn't wan to learn the domain, and started feeling pressure that because I do (now) uderstand the domain, I shouldn't waste my time programming. We made better software when we were all expected to be multi discipline.