I would say it is only half right. Of course, most best communicators in the world are met among politics managers, as being able to correctly express themselves is an essential skill for them to hold their position. Still, we see loads of examples, when politics cannot organize their speech in a proper logical way and managers cannot find a proper way to communicate with people they are working with. Having any kind of power can be dreadful for each person. We are creatures fulfilled with egoism, so the more power we have, the more is the seduce to use for your own purposes or to show off with it simply. It is not a rule, of course, but this fact is one of the most frequent reasons to spoil communication skills or completely ‘remove the necessity’ of being an excellent communicator when you are a boss.
That is a good one, the question, I mean. If you write a paper on it, I envy you so much right now! You can examine this issue from either communicational or psychological point of view. If you choose the first one, you can search for the specific techniques political leaders and managers use. Among the often mentioned are manipulation, NLP, and persuasion. The topic is fascinating, especially after you know the tricks they use, it is so much fun to observe it all.
If you chose the psychological aspect, you could examine whether people tend to consider political leaders and managers to best communicators, as a status is usually followed up by loads of stereotypes, people do generally believe in without any doubts.
Or, even more, you can combine both this aspects examination in your paper, if you need a solid word count.
I have seen a bunch of decent works on that topic, so I’ll leave a few links here for you to have a good start.
Good luck in your future investigation! Take care