Yeah, that's probably it. The mega-church down the road from me encourages pre/post service fellowship by offering free lattes and cappuccinos in a very open, comfortable/welcoming atmosphere, but most are on the move to their next event of the day as soon as the service is over. Small group Bible Study/Fellowship groups are the way to go, and/or grabbing a small group of friends for brunch after church can work too.
At Chuck Swindoll's mega-church in California, they solved the problem by forming churches of 200 or less within the mega-church. Each smaller church had its own pastor/staff, and they do everything together, just like any other church of 200 would do, so that people within each smaller church have a "family" they can know/serve with/be a part of each week. Each smaller church runs its own potlucks, VBS, youth missions, small groups, etc., and then they attend the mega-church services together as well.
The mega-church near me has a TON of $$ and they choose to prepare/serve & feed the poor/homeless in this area 1 meal/day, 365 days/year (the city serves them a second meal/day). So if your church has a church-wide ministry like that, that's another, wonderful way that you can come up with a "family" group within your church to talk to and minister with
~Deut