I simply don't understand why soy milk is so much more expensive than cow's milk.
 Shouldn't it be cheaper, since it's just a matter of harvesting
soybeans and then processing them?  There's no "middle cow" to
purchase, breed, maintain land for, innoculate, etc.  In addition, the
shelf life is better - ie - less milk goes spoiling on shelves if left
unsold.
 If someone could explain why soy milk is still more expensive despite
what I think are cogent reasons for it not to be, I'd appreciate it.

Here's someone who agrees with you:
http://health.groups.yahoo.com/group/notmilk/message/1135

I haven't been able to verify this, but I assume there are two main reason:

1. Economy of scale. The more of something you produce, the less it
costs per unit because many costs are fixed (or relatively inelastic)
regardless of the amount of production.

2. People who want soy milk are willing to pay more.

Also govt programs (USA) significantly support farm prices, in return
we get exessive production and hude stockpiles of butter & powdered
nilk, as well as american cheese, filling up govt warehouses.  Soy
milk doesn't "benefit" this way!

Soymilk

The cost of a product is not only the cost of the raw materials that
go into a product.  In point of fact, these costs are often
insignificant compared to overall costs.  Everyone has heard of how
little the cost of wheat factors into a loaf of bread,

"One bushel of wheat can produce 71 loaves of bread, Kiser said. The
cost of wheat in each loaf ranges in price from 5 to 8 cents. If wheat
prices rise, the cost of the wheat in the loaf of bread goes up by 2
cents. "
              http://www.kstatecollegian.com/issues/v100/su/n163/city-wheatprices-classen.html

For soymilk, I'm going to use Vitasoy as my example below.

If you just look at soymilk factory costs, Vitasoy runs a healthy
55.9% gross profit.  For factors that go into factory costs (see
citations 1 and 2).

And if you looked only at that figure, you would say, that Vitasoy
could cut what they charge retailers for their products in half and
your local store **would pass the savings** on to you.

Ahem.  

Not.

In reality, the local store would pocket the difference as their
pricing strategy is to charge a premium for soymilk versus cow's milk 
 And it works - because you buy.

However, we don't have to worry about the local retailer's moral
dilemma as Vitasoy loses money in the United States (even with a 55%
gross profit) once you add in all of their marketing, selling,
distribution, and administrative and financing costs. See citation 3.

USA Subsidiary continues to loss money  
             Hong Kong $ '000
   2003                2002             2001
  (35,401)         (51,573)          (23,699)

The single biggest cost was new product launch for refigerated soymilk.


Now you may think this is terrible!  The cost of goods sold in the
United States have almost nothing to do with the cost of raw materials
that go into those goods.


Start Personal Opinion -- --- -- In point of fact, this is one of the
greatest economic achievements in human history.  It has lead to the
widespread distribution of wealth and the creation of a middle class
society.

Think about what it would be like if raw materials were half the cost
of a product.  Who would get the money?

The farmer (farm factory) or the miner (mining company).  But the
number of people who work at farming and mining is well under 5% of
the workforce --  and  if half of all the money in the United States
would flow into their pockets (or, more accurately, the pockets of
companies that own the farmland and mines) then the
salaries/income/wealth  of everyone else in society would have to be
cut drastically.  It would probably decimate the middle class.

There is a reason why no large scale middle class society was possible
before the Industiral Revolution.

End of Personal Opinion.

I hope these references prove helpful in understanding the
non-intuitive nature of capitalism as it applies to soymilk costs.

----------------------------------------------------
Citation 1

TECHNOLOGY OF PRODUCTION OF EDIBLE FLOURS AND PROTEIN PRODUCTS FROM SOYBEANS
FAO AGRICULTURAL SERVICES BULLETIN No. 97
Food and Agriculture Organization of the United Nations Rome 1992
CHAPTER 8
SOYMILK AND RELATED PRODUCTS

http://www.fao.org/docrep/t0532e/t0532e00.htm#con


Go to reference for complete cost of plant equipment.

http://www.fao.org/docrep/t0532e/t0532e15.htm
EXAMPLE 5:
Soymilk Plant, INTSOY (Illinois) process,
220 liters/hr.
Source: BAR EXPORT/IMPORT, INC. URBANA,ILLINOIS
Date: 1990

TOTAL, F.O.B. Seymour Illinois,Export crated: $ 220,052.00
OPTIONS- BUDGET ONLY
Blending- for different flavours
(using the same packaging as soymilk) $ 38,000.00
Yogurt a.) 72 quarts/24 hours, manual filling $ 12,000.00
b.)144 " " " $ 22,000.00
Ice Cream- 100 Gal./hr., semi-automatic filling,
100% overrun. $ 45,000.00

------------------------------
Citation 2
For detailed economic information, including total capital
requirements and operating costs, we refer you to Alfred Batholomai's
"Food Factories" (VH Verlagsgesellschaft, Weinheim, Germany) which
contains chapters covering a complete Soybean Oil Extraction Plant, a
Soybean Oil Refinery, a Tofu Plant and Soymilk Plant.
---------------------
Citation 3
Vitasoy Annual Statements of Profit/Loss
2002
http://events5.broadcastone.net/0345/20020710/pr_eng.pdf
2003
http://www.vitasoy.com/en/pdf/Vitasoy_e_030709.pdf

USA Subsidiary continues to loss money
   2003                2002                 2001
  (35,401)         (51,573)             (23,699)