Caravans are always going to be primarily the preserve of families or older people I think. When I was young we caravanned every summer with the family which was great, but when I left home I could barely afford a little Citroen Saxo let alone something big enough to tow a van (and then buy the van too!). Also at that age if I wanted weekends in the wilderness we'd go wild camping in tents, really away from it all with no site fees to play. Beyond that it would be cheap hostelling breaks around the world.
Fast forward to having my own family and being forced into ridiculously expensive school holiday breaks, and a van makes far more financial sense. The extra comforts such as heating, toilet, full oven etc make it far more usable with a very young family than a tent, particularly for short weekend breaks where the set up time on a Friday night after school is minimal compared to pitching a behemoth of a tent.
One thing though, I was obviously very lucky without knowing it when younger as the site we went to in Cornwall every year was beautiful - outdoor pool, games room / table tennis and outdoor play areas for kids, a few organised activities such as games of rounders but no bar / clubhouse on site so still lovely and peaceful. I've been surprised when trying to find similar sites in my region (East Anglia) how few and far between they are! Most are either much smaller and more basic (which can be fun in itself), or bigger with bars, discos etc which I don't want. There must be a market for more sites like I went to as a child, and I'm sure that would help more people to get into it.
It's also interesting what Martin24 says about youth clubs - I'm in the CC and had no idea of this, worth checking out for my kids as they'd love that - so agree they should push this more!
And yes, lightweight, quality family vans at reasonable price points are a must. Most people don't want to have to buy a huge SUV or similar for the few trips per year they will take with their van, you need plenty of options towable by a standard family car.