Bing is under Qi Lu, full stop. Lu is very senior VP who reports directly to Satya Nadella. Bing is NOT split among Qi and 4 of his VP peers. It IS true that Lu has split the responsibilities of managing Bing up among SOME of his direct reports, almost all of whom are themselves VPs. But the idea that there is no real "Bing org" anymore is just completely and totally wrong. They all answer to Lu, and they've split responsibilities along sensible boundaries, so that things like UX are under one VP and infrastructure is under another VP.
Second, Bing does not have 20% market share "plus" Yahoo's market share. Bing and MSFT properties like MSN have 20% market share. Yahoo has 12%. You can't just credit Bing with Yahoo's market share. That's a search experience they work hard on, and the fact that Bing powers Yahoo is largely immaterial to their consumers, who come to Yahoo for the Yahoo experience. They could switch to Google tomorrow and the vast majority of consumers would not notice or care. Truthfully, the biggest (and arguably only real) benefit for Bing is the increased ad revenue.
Third, Bing IS profitable. This is well-known and reported on.
Fourth, it is basically completely untrue that "nobody" buys Bing ads. Obviously it would not be profitable if that were true. Furthermore, the supposition that you should buy ads based on market share of the search engine is hilariously wrong. You should purchase ads on the platform where they will be more successful. A lot of times this is Google; sometimes this is Bing. The fact that the parent got this wrong basically indicates that they are not to be trusted on this subject, at all. If the poster doesn't know what they're talking about here, it's better to just stop talking then it is to provide information that is wrong or harmful to people listening in.
Bing traffic by and large tends to be older, more affluent, and less tech literate... people who don't tend to change their default search engine. For many types of businesses, this is ideal. Also we have had good results in tech B2B marketing with Bing. My theory is that most MS sysadmins don't want to run chrome on their servers but surf from their boxes and get lazy. Also porn.
The big story with Bing is its tight integration with Windows, XBox, Cortana, etc. Their research direction per Stefan Weitz has been to focus on making natural language search really work. Less effort has been invested in trying to keep up with Google and more has been trying to create a different search experience.
When Cortana really hits the main stage this summer/fall, we'll be seeing the manifestation of Bing at its fullest, and if they really get the Neural Networks nailed they could pull off a big shift in how people search, and also how people advertise...