Voters may want to read the other writeups first.
I have long pondered the reasons for talk shows being so popular. I have come to the conclusion that it is two main factors:
Firstly, most people have boring lives. They want to pry into other people's lives and look at their 'problems', and to think 'I'm glad MY wife hasn't said she will only forgive my adultery if I will dress in drag on national TV!' or something like that. A sort of surrogate interesting life for people who don't have one, rather like that other popular TV institution, soap operas.
And secondly, talk shows are cheap to produce. You don't need computer graphics, fancy sets or makeup, as you would with, say, Star Trek. You don't need lots of actors, who start demanding high wages, like with soap operas. You don't need skilled scriptwriters. You don't need a dedicated film crew who work all through the day in case something interesting happens, like you do with a docu-soap. You just need a room with some tiered seating and a stage-like area, some cameras (hired if need be), and a host (Who doesn't need any real qualifications).
So, you have a program that is watched by many people, and which you can produce for next-to no money. This is clearly attaractive to television companies. Resultantly, they are popular schedule-fillers.