While legislation prevents them, it also protects them. Do you really think that Channel 7, a business that makes irs money from selling adverts, wants to have multiple signals?
How would they sell time to advertisers if they are splitting their own audience? I mean an Olympic adveriser may be a little pissed at 7 watering down their own viewer numbers by competing with themselves.
I remain entirely unconvinced that the FTA's really want to compete with themselves in this way.
They could do smart targeted advertising. For example, run women directed product ads during the gymnastics on one channel, male directed ads during the soccer or boxing on another channel, general interest ads on another channel during the swimming on another channel. Five different ads for five different products running on five different 7 network channels