I believe RVing and camping is a lifestyle choice. Just like those who "travel" are making a lifestyle choice. The debate about whether or not its cheaper has as so many others already pointed out... many variables. Can it be? Yes, it can.
For me and my family, we decided it is cheaper. To start, there is the tow vehicle which will get less gas mileage than a sedan or even a mini-van. For me however, I hunt, and use my pickup truck for all sorts of things and only drive 4 miles to work. A pickup truck fits into my lifestyle with or without a Travel Trailer. So I dont include this cost in our camping.
Secondly, we have room to keep the Trailer at our house. This is hard to do if your renting or just have a small drive way or lot.
I have 3 kids under the age of 8. Traveling to another state, or over seas for 4 weeks a year at different times a year will be way more expensive than our monthly Travel Trailer payment and campground fees for the year. In fact, I tallied up and was able to figure out that for one year, our entire camping budget would only get us one week of vacation if we flew to Florida for only one week. Thats savings!
I believe camping is healthier for a family. With camping we are not eating out, we are eating at the campsite. Not only is this cheaper because its just a regular grocery budget, its also healthier should we choose to make it so by eating healthier foods. Also, because we are camping for 4 weeks a year vs. 1 week of flying to Florida or elsewhere, we are getting more time together that is away from home together as a family!
More recreation is another benefit of camping. We always bring along our bikes, fishing poles, footballs etc... You can bring along canoes and other recreational items which is again.... healthier than just sitting around a pool at a resort for a week!
Lastly, getting the next generation in the outdoors is imperative to me. I believe we are losing this generation to the gadgets and gizmos that technology provides. I dont condone this at all, but getting kids in a campground where there is no internet, and limited cell phone service and away from other distractions (especially with the whole family) is refreshing for them. They may complain and never thank you, but in the end they do have a lot of fun and it will make memories that last a lifetime and almost always passes on to their kids when they start to take them camping!
So again... its a lifestyle choice and budget choice. If we had only one child or no children we probably would not have purchased the trailer and done resort and hotel vacations.