So you're talking more about talk radio style DJing than a guy on decks/CDRs?
I wonder if the popularity of podcasts could be something related to this. Perhaps I'm not very representative of people but I spend a lot of time (when not listening to music) listening to talk-radio style podcasts and audiobooks.
My pretentious theory regarding this would be that people long for personal contact in a world where its becoming increasingly rare - i.e. travelling across a city, not seeing anybody you know, with your ipod on ironically in order to avoid having to hear the real world or deal with it. In societies of y'olde, you'd have been spending all your time in the company of close friends and family, talking all the time.
Banks having DJs - a way to ingratiate themselves with customers, as if they're not a big greedy corporate brand but a MATE (See also: matey adverts with bankers in suits doing dance routines and singing Who Let The Dogs Out). Even that could be related to my abovementioned pretentious theory, couldn't it? We like to think we're surrounded by mates when we're actually surrounded by HEARTLESS CAPITALIST MACHINERY.