What goes into determining the tea in your cup? Supply and demand, surely; but what determines each of those?
Let's consider demand first. If you are the end-consumer (and bear in mind that retail vendors and other suppliers may also be consumers, indeed some of the most passionately interested consumers), what you decide to purchase will be influenced by your knowledge and experience. Experience is itself a potent form of knowledge, and those consumers who are repeat buyers of a given tea will naturally tend to rely on what their experience has shown them. If you favor one particular vendor's dian hong, you are liable to go back to that vendor for more of the same tea; and the confidence that those transactions engenders may inspire you to try other teas from the same vendor -- or similar teas from other vendors.
Moreover, as with most consumables and other amenities, increasing knowledge of tea and tea culture is likely to induce the consumer to become more involved with tea and tea-drinking. This can happen in any number of ways; it may entail searching out new vendors; joining online fora or reading tea blogs such as CHA DAO; purchasing teaware that one had, not so long before, not even heard of; and, in what we may call (ahem) extreme cases, traveling to tea-producing lands in order to observe tea culture at its very fons et origo.
Supply, on the other hand, is directly tied to both nature and culture. Nature, certainly, in that all 'tea' in the strictest sense is made from the leaves of camellia sinensis, a plant not likely to thrive north of growing zone 7; and culture, in that tea involves some degree of processing -- if nothing more than plucking the leaves, drying them out, and then decocting or infusing them to make a beverage. Tea, one might say, doesn't just grow on trees; but to the extent that it does, it also requires people to prepare it -- harvest it, process it, package it, sell it, ship it, sell it again, perhaps ship it again, and then brew it. If there are inauspicious growing conditions (nature) or insufficient or inefficient farmers, tea-masters, or vendors (culture), supply will falter. The converse is also true: when nature and culture align in such a way as to favor the growth and production of tea, the supply can (and perhaps will) increase.
Laowai, and indeed all those who live outside the tea-producing regions of East Asia, are at some remove from the variables in the economic equation surrounding the supply-aspect of East-Asian tea, whether in reference to supply or to demand. Even the avid and dedicated tea-drinker in Charleston or Dubuque may not be aware, for example, that Yunnan province has been suffering from severe and extensive imbalances of rainfall -- in terms both of droughts and of floods leading to landslide. And there may be more thoughtful, educated people than we think who are still unaware of the dramatic rise and fall in demand for pu'er tea in the past few years.
But westerners generally, and Americans in particular, would really have to wilfully shield themselves from the daily news in order to remain unaware of the gravity of the national (and indeed global) economy. We are currently living through what some call the worst recession since the Great Depression; and in such times, all but perhaps the very wealthiest tend to trim their spending in some way. Such a practice calls into question whether one can make the case for including high-end (or 'premium,' or 'rare') teas as part of one's monthly budget.
There has been a great deal of talk recently about the notion of 'affordable luxury,' and along with that, about tea as an affordable luxury. That tendentious phrase may not be as clear as it initially seems; even for the middle classes, what is 'affordable' for one household may be quite extravagant for another. But one thing is certain: as supply and demand are synergic, affecting one another in active and reactive fashion, everyone in the chain of commerce -- not just the end-consumer -- is going to be affected. That hard-working and trusted tea vendor that you rely on may be working within a very narrow margin of profit; if the growers cannot get a viable price for their crops, they may not still be growing tea a generation from now.
All of us, Asians and Occidentals alike, wish we had a simple clear answer to the conundrum of the global economic problem in general, and of the tea economy in particular. Manifestly no one does. Perhaps we should honor this massive ignorance as the epitome of the human condition. As Laozi writes (Dao De Jing 1):
[xuan zhi you xuan, zhong miao zhi men ('Darkness within darkness. | The gateway to all understanding'; transl. Stephen Mitchell)] -- we may have reached the limit of our understanding at the moment, the brink of this cosmic darkness (玄 xuan), where the only way out is through. If so, we could do worse than to cling to that Japanese proverb so beloved of tea-drinkers, 一期一会 (ichi-go, ichi-e) -- 'one moment, one meeting' -- and to celebrate the richness of the present by drinking tea with friends.
On the other hand -- if I may direct my gentle reader's attention from the east Asian to the Greek tradition for a moment -- we may want to take some inspiration from the ant as well as from the grasshopper, finding a way to plan for the future as well as living in the moment. In practical terms that may mean developing one's own personal 'tea stimulus package' -- laying in as much good tea as one's purse can bear; and, in the process, spending in such ways as best to support those vendors that one appreciates and respects the most.