This line interested me greatly: But because TV reaches a much larger audience [..] when considered on a ‘cost per viewer’ basis, its greater expense is not qu

This line interested me greatly: But because TV reaches a much larger audience [..] when considered on a ‘cost per viewer’ basis, its greater expense is not quite so pronounced. Is this an assumption they're making? Is using the TV to reach out to people cheaper than the radio? The reverse holds true for India (All-India Radio reaches way more people than Doordarshan (state-sponsored TV channels)), but that's a different situation - radios and radio coverage across India is dramatically cheaper than that of television, and radio advertising is orders of magnitude cheaper than on the telly.