They are mostly not convincing the people who have to do the work. Instead they convince decision makers higher up, who in turn tell some group to go do the work.

For that, it helps to have good sounding ideas, some existing successes that can be claimed, and to have good people skills. These things wind up being more important in the end than technical competence.

(I gained an appreciation for these dynamics from working at Google back in 2010. Everything that I've seen since has confirmed the importance of this dynamic.)