It is probably the timing that accounts for the nature of reality TV. After all, why call something "reality," which is really such a broad category, and then have it become a sort of genre? It seems as though the word itself is a reaction to the sitcom or the drama, which has to be constructed, and is often predicated on various ideals. Or at least, the act of deliberately putting a plot together means you have to be thinking about some sort of guiding ideal.
But then you have this waving away of the ideal: let's present reality with all of its grit. And what you see when you get tired of ideals is just a smattering of dueling egos and conflict, and it eventually it becomes so that the "reality" is really just executives and producers getting together to see how they can actually "construct" and maintain the drama and egotistical conflict that fans have come to expect.
