Of course he whole idea is nothin like new. Back in the 1970s they seemed to start as far as I can recall, US TV studios would try formats and if they worked then a series was commissioned. Into the age of videos and then dvds, when old shows have been rediscovered, a pilot episode is often the first episode of a dvd boxset.
When the UK only had 3 channels, US TV shows were massive on all channels, the Starsky and Hutch pilot was so hyped at the time and so was Kojak, before that there was the Alias Smith and Jones pilot that was advertised for weeks,