Follow-Up: For you-know-whats and giggles, I decided to check and see how another year adds up (aka, I randomly stumbled upon this post). I listed last year's final results, in addition to 2016's.
2015: WLS- 8.1, WMAQ- 6.7, WBBM- 3.0, WGN- 2.7, Combined- 20.5 / 34.7 Share
2016: WLS- 6.6, WMAQ- 5.3, WBBM- 2.5, WGN- 2.2, Combined- 16.6 / 28.0 Share
How fall did they fall? WLS- 1.5 (-19.5%), WMAQ- 1.4 (-20.9%), WBBM- 0.5 (-16.7%), WGN- 0.5 (-19.5%)
Interestingly, the losses were essentially proportionate, so no one station really suffered more than another, percentage-wise. I'll maintain that the Cubs likely had an affect during the first week, but NOW they all can definitely look with worrying eyes at the numbers, especially if said team strings a few good years together. For what it's worth, simple math says only about 8,000 more households were tuned in overall this year in that time slot compared to last year.