slydrite- I agree with you about autox, but I've got a good friend who's one of those with the expensive trailered car and I've spent much time trying to convince him to come roadrace with me.
His point is that its a good family racing hobby when compared to roadracing. They have one very built evo which 3-4 family members each get to drive. They spend a sunday or two a month at the track with their whole family and everyone gets to compete. When you have young kids, they have a dedicated class of kid karts, and as soon as they get their permit or something they can drive the family racecar. Plus, they can afford to race a fire-breathing monster of a car for just a couple hundred bucks a weekend, instead of thousands. No risk of wadding the car, consumables are pretty cheap etc etc.
So while roadracing is definitely a good time, autox lets lots of families enjoy racing at a pretty high level with much less time/money.
Granted, once you get very serious about the time investment is probably just as high, but at that point it is a part of your life, and so trailering the car halfway across the country for 10 minutes of track time is really not significant in comparison with seeing all the old buddies, going for the championship etc.