First of all, I'd take my opinion with a grain of salt as I have never worked in a corporate setting and every company I have worked at have been very developer centric with the minority being non-technical personal.

I do think the ability to communicate effectively is always important regardless of who you are or what you do as others have said. As far as developers specifically struggling with problems with communication I think that it depends on who they are trying to communicate with. I can't not remember a single developer I have met that had significant difficulty communicating to other people who are technical. Pretty much every one I have met has been quite articulate about technical matters and appear well versed in rhetoric. Now this may be skewed since if in fact they were not able to communicate with other developer then they would not be able to communicate well with me.

This being said I have met developers who have struggled with communication with non-technical personal, but my personal opinion on this is it's the result of a lack of a shared vocabulary with things as oppose to a lack or oratorical skills on ether side.

As far as whether learning oratorical skills and technical skills are mutually exclusive, while they are not the limiting factor is time. I have an ever growing list of languages I'd like to learn, frameworks I'd like to try, work I need to do and side projects I'd like to start. That does not even include my interest in becoming better at design. Even with the little sleep I do get, I am not able to keep up with what I would like to do and I would prioritize these things over learning oratorical skills. But again that is a personal opinion and choice and it is likely there are other who would disagree with me on this.