But it is. And it's a key component in the metrics of media, which only has a few parameters:
1) Size of audience - producers think they exist to 'tell great stories' or 'produce great programmes'. Bollocks. They exist to deliver audiences; they may be one step removed through broadcasters or distributors, but if their programmes don't delivery an audience, they're toast.
2) Value of audience - how well can a specific audience be monetised through subscriptions, pay per view and advertising (or gambling, eShopping, etc..).
3) Engagement - how involved are users with the content. Most viewers will go 'oww! Midsummer Murders, excellent, I'll watch that...' as long as it's free. But with Man U v. Man C there are people who will die if they miss the match. That's engagement. And it's the reason why ten football fans are more valuable than a thousand Midsummer Murders fans.
And this, dear reader, is what drives television and all of our media..