In my opinion, this is due to the fact that until only a few years ago, most westerners had very little exposure to Chinese culture in any way whatsoever. Although other countries have tea traditions as well, many of those traditions actually come by way of the British and their attempts to develop new tea-producing regions in the places they controlled.
Of course, the tea commonly used in the U.K. is not good quality compared to what is often seen in the tea cultures of East Asia. As a result of this, few westerners were exposed to the fact that tea is not just something prepared with tea bags — that tea is more properly prepared from carefully processed loose tea leaves of high quality. For most of us westerners, “tea” was just the low quality tea bags found in grocery stores.
