Remember the days when the only option for a living room was three piece suite. Two chairs and a sofa, all matching. To be fair it was an attempt to create a social space in homes. A place where people would gather and chat or watch television whatever was required.
Over the years it hasn't changed so much people still like to sit and chat or watch an open fire. However the 'social space' has been more interesting in recent years as people like to experiment with different styles and express their own styles while designing a space that works for them.