"only as good as his reed"
Well, I don't know about that... A great player doesn't crumble because of a clunker reed. An important developmental step for every player is learning how to get the most from your reeds - and to make them do your bidding. Sometimes that means changing what you "know" is right. Try changing your reed storage habits, try leaving it on the mouthpiece until it dies, try a different break-in period/method, get a reed knife and use all those bad reeds as experiments, try a different brand or cut or strength. When I hear someone say that they can only use 10-20% of the reeds out of the box, I think they really need to try some of the above suggestions! Also, make sure your mouthpiece is faced evenly. For example: if the right rail is slightly higher, you might always be looking for a reed that has a harder right side than left. That's tough because you'll always be searching for a specific imperfection - you might only find that 10-20% of the time!
The fact is, cane reeds are each individual and no method for dealing with them works for every person. It's an important part of the personality of the instrument, so just slapping a reed on and hoping for the best is probably not going work in the long run.
The comment on the Vandoren reed-making process is accurate, and that is probably a similar process as other manufacturers. First, the cane is cut to a manageable size, dried in the sun, stored inside for a matter of months or years. Then when it's ready, it's cut into cylindrical pieces the size of soda cans and sorted by thickness - wide pieces for bari/bass cl, small ones for soprano/cl, etc. Then it goes through a series of maybe 10 machines that each cut a certain aspect of the reed very precisely. Under-appreciated fact: all reeds of a given instrument and cut (like for example V16 alto) are cut EXACTLY the same. Differences in the cane account for various strengths. So a 2 is not any thinner than a 5, the cane is simply softer in the 2. After the reeds go through the process, one of the last machines presses on the tip and measures a precise strength index number. The ranges of index numbers are grouped into categories of strengths (2, 2.5, 3, etc.) which are then stamped onto the back of the reed.
There are a lot of variables that go into how a reed plays. Since the only way a reed is tested for strength is how the tip responds, that doesn't account for things like an uneven cut b/c of an out-of-round cane or cane that varies in hardness from the right side to the left. High quality manufacturers try to get rid of the bad cane right away (scanning machines do this quite effectively), but as we all know, the most perfect-looking reed doesn't always play that way.
Another surprisingly common misunderstanding: reeds are not made from bamboo. They are made from cane. Bamboo is a tree, cane is a grass.