One thing my wife noticed at the Pumpkin Cross was all the kids. We had met up with another friend who came to race as well. After some uncomfortable discussion, he came by him self and left his 3 kids at home because his wife wasn't interest in coming out.
It appears the average CX racers is thirt/fourty somethings with kids. If organizers had some sort child minding program, lead by a teen, you might get more racers out. Im sure there are some wives that don't want to come out to races and don't want to be saddled with the kids at home while the dads are off racing for 4hrs. So the dads don't make it out.
The child minding would really only be for 30-45mins at a time while the race is going on. Seeing CX racing is pretty self contained it wouldn't be hard to set something up with activies of sorts in the middle of the course or near registration. Just a thought.
I fully resemble that demographic! :-)
The kids races are fun but if the kids (with or without spouse) come out then you generally get a shorter warmup (arrive closer to start time) and much less hangout after your race (leave before awards). The vibe at many is generally family-friendly but I'd second mattbc's thoughts on finding activities to keep the kids happily occupied when they've gotten bored of watching racers go around in circles!
An on-site child-minding / kids-activity service is an interesting idea - I'd be willing to pay for that!
Courses with playgrounds (that are not used in the course!) help in this area.
Any sponsors willing to supply a bouncy castle? Ha Ha!