I don't know to many folks who's RV needs were the same between their first and their last RVs. Although I agree Airstream makes a good product that will likely last -- is that one trailer really going to satisfy you?
Good question. Maybe Airstream is not a 'starter' trailer and folks might want to get their feet wet with a standard box trailer to see what they really want in an RV. But after that..........yea, I think I would know what I wanted and was willing to invest in it.
As an aside the entry fee for Airstream is clearly higher than most other RV trailers. So is the resale, so in an economists way of looking at life cycle costs, the difference in money initially invested and later recouped by resale might not be that much more than a less expensive box trailer that in five years is worth half of new and in ten years only a fraction of new. The economic difference being that more of the customers/owners money is tied up in the Airstream until sale day than with the box trailer. But at the end of thirty years of RVing the Airsteam was purchased once, the box trailers perhaps three, four or five times and at the end of it all the Airstrem might have been a more cost effective RV.
When I purchase anything large, I always lookd at resale and what it really costs me to own it in depreciation. It can be a real eye opener and the 'faint at heart' should never put a pencil to the numbers of a new RV as the depreciation is sobering. The payments might be $200 a month on a new trailer, the depreciation will be that much as well so the cost to own outside of maintenace, insurance, taxes, and usage is twice the payments. Twice as expensive as most people think.
Economically, the smartest thing we can do with a product that has the kind of depreciation that an RV does is keep it forever, hence my original comments re Airstream. And since most box trailers will barely last through the payments Airstream has the advantage. But, for those that just want new every five years (actually the numbers are 4.2 years) then go for it. Who cares, it is the way somebody wants to spend their discretionary money. I am cool with that.