This explanation cannot stand history check. When broadcasting worked over radiowaves, and press required literal printing presses, the entry barrier to become a medium was several levels of magnitude higher then it is today, and consequently grip of corporate power was stronger. One may say this is why public had better opinion about media - because it was a closed club, or a caste if you like, and media's dirty laundry very rarely had a chance to appear before everyone's eyes. Not because media were better, but because consolidation let them sit on their pedestals unchallenged. And btw we should stop pretending that growing audience cautiousness towards mass media is some kind of problem.