I get the feeling Channel 5 never really wanted normal Big Brother because it's a huge commitment but they couldn't just have Celebrity Big Brother.
The main reason they got it in the first place was so they could fill The Daily Star with stories from it, and they could do that more with the 'celebrity' version. The synergy worked both ways, they had a newspaper that got content from the programme and the programme got a national newspaper that publicised it every day.
Now that connection is lost its a lot less attractive to the broadcaster
That was a reason for buying it but it wasn’t the main reason. Let’s not forget the first episode on Channel 5 got over 5 million viewers, that will always be one of the channel’s highest ever ratings. As it left Channel 4 it was a tired show that was pulling lower ratings than at its peak but still very strong figures and it was, and remains, and extremely cost effective show. It made total sense for C5 to buy it, regardless of who owned the channel at the time.
People have argued that C5 killed the show by airing it twice a year but ultimately the show has served the job that C5 wanted it to. Even if it has been overkilled it’s still managed to average roughly 2 million per celeb series and about 1.5m for the regular series, strong numbers for the channel. It would make no business sense to have fewer episodes a year when you’ve got figures like that coming in and a yearlong bill on maintaining the house.
Ultimately Channel 5 is a different and stronger channel to what it was when they first bought it and the civilian series in particular is starting to stick out like a sore thumb in the schedule (see this week with the heavily trailed Michael Palin in North Korea followed by BB!). Like Channel 4 in 2010, Channel 5 want to move in a new direction and Big Brother is the victim of that.
The show won’t be bought by anyone immediately, it will have a number of years off before eventually returning somewhere to a lot of hype and much higher numbers.