Reality shows are sometimes preferred by networks, because of the money saved by not having to pay scale to union actors, since they can hire non-professionals. We tend to think of this as a new phenomenon. But some of what is called "reality tv" is one of the oldest form of broadcast programming - which is the traditional "talent contest." American Idol and all of its spinoffs - i.e., "The X Factor", "The Voice", and so forth are musical talent contests with amateur contestants. That goes way, way back to "Ted Mack's Amateur Hour."
Some of it also is based on traditional game shows or competition shows- that's the premise of The Bachelor - with contestants competing to be chosen as the winner.
Andy Cohen over at Bravo, executive producer of the "Real Housewives" series is facing a lawsuit, plus an attempt by his employees to unionize. There's all sorts of news on the reality show scene. Because the genre is so ubiquitous and so over-producted, it's losing a lot of its audience. JMO - D.