One of the biggest factors of the decline is money, especially with the current economic downturn. Many have to decide between necessities much less being able to afford to bowl especially when league fees will eventually go up, and some even cite the cost to sanction (I personally have no qualms with my current sanction fee and it's probably one of the highest including state and local).
That's not it though. There are other factors too. There are other activities to do that are also one time deals
, or commitment free. Then there are the bowlers with kids that have their own activities that the parents need to take them to.
Some of the decline is also from not getting enough new bowlers into the mix including kids. With all the other activities for them to be in including other sports and playing video games as much as possible they don't see bowling as a serious activity.
In reference to the original post, I see it more as a way to get word out of this new site and not really talking about the issue in the topic title. A online league has no relevance with fighting the decline in real league bowling.