Regarding the bolded portion of the quote, I am not necessarily sure if that is true. According to
this analysis (with kind of a weird way of looking at things), interior DL is the 2nd most valued position in the NFL draft (just behind CB). And if we compare the 2017 cap hit numbers between DE and DT, they come out pretty similar (top 5 DE average $15.16 mil, top 5 DT average $15.15 mil; top 20 DE average $10.55 mil, top 20 DT average $10.26 mil).
A dominant interior DT, one who can command double-teams and still wreak havoc, is almost impossible to game-plan against. For the extreme example, see college
Ndamukong Suh. In the name of getting the best players on the field, I could definitely see him playing some DT early on.