I think this phenomenon is mostly a macro trend. The 2007 Cubs averaged 40,153 and were 6th in attendance. To compare to a more recent emergent season, the 2015 Cubs averaged 36,540 and were....6th in attendance. This year is a step below that at 34,373 and 9th, but this team had less pre-season excitement and looked dead in the water as late as mid-July so I think there's other potential explanations. If next year's team is competitive most of the way through the year and they're still struggling to break a 35k average, that I'd put more on the Wrigley/Ricketts-specific component.