Natural alexandrite is not better than synthetic alexandrite but natural alexandrite is very rare and uncommon in modern jewelry because it is hardly ever available and because it is too expensive for the general public to buy. Even lower quality more included stones are expensive and very limited in supply. Alexandrite was used in antique Russian jewelry and smaller stones were also occasionally used in Victorian jewelry from England. The few stones that are produced today are usually snapped up by collectors or jewelers and mounted in special settings by designers. Alexandrite is not a mass market item and each alexandrite is individual. It is almost impossible to find two stones that display exactly the same colors under a variety of lighting conditions unless they are cut from the same crystal.
Synthetic and simulated gemstones are accepted and popular in certain segments of the market and much of this is may also be due to the recognition of these gemstones for their own merits and not just as substitutes for natural gemstones. Even people that can afford the natural product often like synthetics because they look great and are affordably priced. They may also be more comfortable wearing them because they don't have to worry much about theft. In the case of alexandrite, the synthetic version is not only much more affordable, but it is actually available in a variety of calibrated sizes and shapes which could never be offered in natural stones. There are several manufacturers of synthetic alexandrite and production of large and clean stones does not seem to be limited by any factors other than capital investment in the growing operation.