It all comes down to the prices at the gate. It's greed that has driven them up (mainly greed by the old firm because they usually fill their stadiums). Clubs must see that a reduced price will get more through the gates.
The old firm seem to set the bar though for gate prices throughout the league. You can't have one team charge £20 odd when eveyone else has reduced the price to say £10 so the price has to stay around about the same throughout the league. In saying that Hearts did didn't they?