Who are the equivalents of olympic champions for soft/social skills? What occupations do they usually hold?

I would expect to find them among lawyers, marketers, fixers/facilitators/deal-makers. Red-pill people probably want to be there, too :-/

What is the present day equivalent of the Byzantine courtier

A political operator, playing the usual games in the corridors of power.

the best performers in the cynical management of people so they further their goals?

Steve Jobs was said to be very very good at this.

occupations which select for such abilities

Salesman is the obvious one. There are LOTS of books on how to Win Friends and Influence People :-) starting from the Carnegie classic. Check out your local B&N or browse Amazon.

I no longer remember where I read this idea:

There have always been people highly attuned to identifying whom they need to flatter to obtain favors. Before modern democracy, when sovereign used to equal king, the sycophants trained in the art of ingratiating themselves with the sovereign were the courtiers whom you could always see surrounding the monarch. Now that the sovereign in most Western countries is "We the People," you can find the same sycophants using the same arts to gain favors from the sovereign---they're the PR consultants, political strategists, and most candidates for public office.

Who are the equivalents of olympic champions for soft/social skills? What occupations do they usually hold?

There are many different social skills. The skills of a good coach are different from the skills of a good salesperson.

Trump speaks about he would put people like Carl Icahn into negotiating deals. I think Icahn is at the top of the league. I would put Oprah as well into the olympic chamion category but she's very different from Icahn.

I recall Kaj_Sotala writing up about a friend of his, who was able to do pretty much that, and his drawing a mind-map of conversation topics, and generally, that conversation is just like anything else: you ought to put effort into it, prepare if you want better outcomes, and anything which goes for any complex activity, so goes for this. On the IRC channel when there was talk about AI box experiments, ridiculously long pre-prepared scripts were mentioned. Debate teams also do this

Of course you can have conversations by drawing out possible conversation topics. On the other hand I doubt that the quality of those conversations are very high. Having high quality conversations is a lot about opening up on an emotional level.

I went into my last 4-day personal development workshop with the expectation that while I'm at the emotional resonance with the workshop, it's likely that people will approach me more in public. After the first day I was travelling home (15 minutes walking + 20 minutes driving the train) and two people approached me for navigation advise.

On the second day one person approached me. I thought to myself "This is crazy." That was enough to close down and nobody approached me the next two days.

There's nothing that I could do based on reading a book that puts me into that state. It's all the emotional effect of opening up. Does that mean that I'm generally highly skilled at having conversations? No, I'm not top tier. Most of my days in the last year I was acting rather introverted.

I think you make a mistake if you try to focus on mental work such as mapping out conversation topics instead of dealing with emotional and physical issues.