Perhaps I was misunderstood; the idea is that this polymath would collaborate with the experts and act as a bridge between fields.

Yes, but those polymaths are rare obviously.

Wherefore I mentioned how the same might be accomplished without them, simply by listenening and explaining to each other.

Of course, if you assume individual experts to be really entrenched in their particular fields and entirely unable to bridge the gaps between them, you might be dependent on such talent.

I have never seen a job offering to that effect though?

They ain't the ones in charge either, though I think I agree with the need for such people.

We basically have PR people deciding what's going to look best for them.