Is that average length that much different than the average length of other sports? Seems about the same as the NFL. I'd just venture to say that NFL game times vary a lot less in length than MLB does. I think NHL and NBA games are significantly shorter than those, while NFL is probably as much as 10 minutes longer. The big difference there is of course you only commit to one per week for NFL, but baseball needs the same people to watch multiple times every week to make their numbers work, and NBA/NHL are in between.