Ten paid $55 million to host the Sochi winter Olympics and the Glasgow Commonwealth Games. The Seven Network hardly waited for Scottie dog mascots to return to their owners before trumpeting it had the rights to the next three Olympics. Seven may have paid $170 million.

Television executives love big events. Quick hits, they build egos and short-term ratings, but the profits are not always worth the outlay.

The truth is that reality TV is the real bread-and-butter business of commercial television. It is the most-watched and most popular form of television entertainment in Australia and around the world.

Big Brother entered Australia in 2001. In the 13 years since, some 150 reality TV shows have been served up to Australian viewers.

Many died. But Big Brother, Dancing With The Stars, The Biggest Loser, Australian Idol and others have a sort of eternal life. Last month, before starting its Commonwealth Games broadcast, Ten pulled 1.7 million viewers for the sixth season finale of MasterChef.

The genre is so pervasive that even the ABC wants a piece of the action.

Its new show, Reality Check, starts on Wednesday. Using local and overseas shows, it will dissect the week in reality TV. Until now, apart from academics teaching media and sociology courses, few have bothered to take reality TV seriously.

Reality Check is serious about the genre. The show features comedian Tom Ballard and industry experts. Sound familiar? It is co-produced with CJZ, the people who make The Gruen Transfer.

Executive producer Nick Murray says reality TV has changed the television landscape and perhaps there are lessons to learn about ourselves from these shows.

‘‘Millions more people watch reality than drama,’’ he says. ‘‘Why? Maybe because it's real people who want something and are prepared to be public about it. We asked contestants why they went on The Block or The Biggest Loser and it turns out they wanted something more than just the fame.’’

Two words define reality television: it's cheap.

The Writers Guild of America says it requires smaller crews, fewer paid performers, fewer sets and can be made for one-third of the cost of an hour-long comedy or drama.

For seven decades, amateurs have cheerfully lined up for a crack at passing fame. The first shows aimed only to amuse.

But years passed and both the shows and the talent took on lives of their own, brilliantly reflecting society’s growing self-obsession and changing taste in entertainment. Here’s a quick guide to the evolution of reality TV:

1948: American Allen Funt created Candid Camera, a practical joke show that filmed people doing silly things unaware and unpaid for hidden cameras. After spluttering around as a talk show segment, it was picked up by the US networks in 1960 (Woody Allen was a writer) and ran for years. Kerry Packer’s Nine Network resurrected it between 1992-96 as Just Kidding, Australia’s most popular show in 1993.

1964: Seven Up started as British documentary on a group of seven-year-olds predicated on the supposed Jesuit dictum ‘‘give me a child until he is seven and I will give you the man’’. The filmmakers return to their subjects every seven years (some have bowed out; one died last year). It's reality TV with a higher mission.

1973: The daily life of the Loud family of Santa Barbara, California, was portrayed in PBS’s fly-on-the-wall documentary An American Family. During the 12-week run the parents' 21-year marriage ended and their eldest son came out. Sociologist Margaret Mead told TV Guide the show was no longer a documentary, but nobody back then had thought of the term ''reality TV''.

1992: Sylvania Waters, a sly BBC/ABC doco take on Sydney’s nouveau-riche in the Shire saw Noeline Baker and Laurie Donaher and their children not only play overtly to the camera but rise above the genre to become the world’s first unselfconscious reality TV show.

2000: Survivor took reality TV to the big US networks. Based on a 1997 Swedish television series, Expedition Robinson, it brought ironing board stomachs to American consciousness. About 125 million watched the first season finale. Now in its 27 season.

2001: Big Brother Australia premiered. Modelled on a 1999 show produced in the Netherlands. Some 1.4 million Australians watched the first season.