I believe he said last year that his girl friend had call him out regarding his lack of commitment to being the best runner because of his eating habits. So he hired a personal dietician/chef. He said it made a difference and was one of the things that helped him in his preparation and training that resulted in a win at World's.
So now, after experiencing the difference a chef made, he seems to be going all in and has hired all these other people to do other things so he can focus more on his job to train, recover and ultimately run fast.
This is not surprising as other athletes in other sports have been doing this for years, and to a much greater extent than Kerr suggests he is now doing.
Pro cyclist teams have popularized the pursuit of marginal gains, which are small seemingly insignificant improvements in performance as a result of sometimes massive expenditures of time/energy and money in pursuit of those gains. But there is much more money in pro cycling than running and it is more of a team sport, so the teams can afford and justify doing whatever it takes.
Its impressive that Kerr is pursuing marginal gains to the extent he is, although I believe his dietician/personal chef will result in the biggest gain for his investment. And his willingness to commit to doing whatever it takes has made me want to root for him much more than before.
It's surprising more pro runners do not do what Kerr is doing. Especially regarding their diet (its shocking to watch some of the top runners share videos of their eating habits).
Whether or not these people are actually working full time for him is questionable. But if he believes they are, it might provide extra motivation for him.