The fact that it's zin doesn't mean that it can't be quality wine. Just because zin wasn't planted in France in the 1700s and classified doesn't mean it's a lesser grape - there is much more to life than cab, merlot, pinot noir, syrah, and chardonnay.
But there has been a lot of branding done for the other grapes - by individual chateaus and wineries and various governments and trade organizations, in concert with writers.
But all that said, if the market won't pay the price, that's the end of the story. Frankly, raising the price of zinfandel will probably do less to help the survival of old vines than lowering the price. If critics knock off a few points just because it's zin, and you have a $100 zin vs a $100 cab, and the first is 90 pts and the other one is 95, the zin is going to end up in the remainder bin, discounted to get it out of the store.
Moreover, although I kind of agree with cdr - I understand the pressures but it's still kind of sad, how necessary are old vines for quality wine anyway? There is a lot of research in this area and aren't the average ages of vines in Bordeaux something like 40 years? They replant fairly regularly don't they? If so, does that mean they're making poor wine?