The TV show has to make a profit or the station wont air it, most TV quiz's have a phone in question thats really easy and a premium rate number to call. shows like 'Millionaire' hardly ever give away a million, but earn millions by idiots phoning up ten times a week trying to win a million, shows with harder questions are watched by more inteligent people, the same people who arnt stupid enough to phone premium phone numbers. hence 'Countdown' doesnt have a phone in, so less prize money can be offered without the show running at a loss.