Why are the business manager interpersonal roles match in the organizational roles for the strategic management ?

interpesonal skills are essential element for successful stratagist and most important one is commanding or leadership skill. A marketeer ll find it hard to successfull without extorvert skills. if interpersonal skills are inline with his required role of organization he ll be more affective in developing, adopting changes and execution of strategy. 

For me interpersonal skill ll define a long term successful role of any kind required for successful strategy.