Although, understandably, tend to look at a modern caravan as a complete package there are, in fact, three quite separate entities which combine to make the whole.
First, we have the chassis and running gear (usually Alko these days), then the internal appliances from Thetford, Dometic, Truma, et al., a finally, the caravan shell itself.
The first two groups are manufactured using very high-tech methods in a computer controlled environment. Quality control is high, reliability is generally excellent and problems tend to be few.
It's a very different matter with the van itself. Make no mistake, it's rather like putting those sophisticated appliances and installing them in a garden shed.
In fact, the average B&Q garden shed is considerably better protected against rot and decay than the average caravan. I know of no manufacturer who uses treated timber in any part of their caravans - not even the German ones.
That's a disgrace, but it's what you get - 20mm untreated softwood framing, protected only by mastic seals that flex and crack (and which may well have been indifferently applied in the first place)
So, they leak, and they rot. They've been doing it since caravans first became popular, until the advent of bonded construction in the very early 80's repairs could be effected without too much difficulty - a structure comprising separate wall board, internal frame, and exterior aluminium skin could at least be taken to bits and reassembled.
Not so with 'bonded' - that alu/polystyrene/vinyl board sandwich was hailed as a major breakthrough when it first appeared. In reality it has been a disaster for consumers. When (and it is 'when, not 'if') the water gets in repairs become very difficult indeed due to the composite nature of the materials.
So you would assume that manufacturers would have taken Herculean steps to stop the water getting inside in the first place, wouldn't you? Well, they didn't, they don't, and given the imminent demise of caravanning due to external factors, they most certainly won't.
They long ago realised that if they presented the complete caravan in an attractive way, consumers would be too busy 'Oooing' and Ahhhing' over the latest gimmicks and gadgets to notice that the caravan they were viewing was still built in the same old substandard way - and, give the manufacturers their due, they knew their market and were quite correct in their belief that they could get away with selling vans that were destined to leak as surely as the sun is going to rise in the morning. That shiny new van might look like it's rolled off a precision robotic production line like a car - but, in reality, it's crudely made by an industry that sees no real need to mend its ways.
There is absolutely no need for those aluminium seals these days! - radiused acrylic capping, Sikaflxed in-situ and the use of properly installed Seitz windows would have eliminated about 95% of the problems - but the customers kept buying rubbish, and who can really blame the manufacturers for continuing to supply it?
Now it all far too late - I doubt if there is a single manufacturer who believes that their will be a caravan industry in 10 years time - so they certainly aren't going to start investing in new technology now. The name of the game is now 'Grab as much profit as possible before the spring dries up' - and that means make 'em cheaper and sell 'em for more.
Oh, they'll pay lip service to 'quality' - but they've been doing that for the last 30 years. These leopards are too old to start changing their spots now