Hello All,
For what it's worth Michael, you make a fair arguement regarding speculation for 3-letter .com domains.
As I reflect on your point, I too see that it is indeed true that the prices of most all investments are based on speculation and yield (such as stock prices, real estate, classic cars, art). Buyers are paying higher prices for such items as they believe their purchase will result in a higher return (now and/or down the road).
In the realm of 3-letter domains, they are relatively rare and do tend to be valuable for several reasons:
1. 3-letter abbreviations are very common and easy to remember. So much of our business culture operates in abbreviations, as does our society. Whether they be 2 or 3 or 4 or more letters, the fewer the letters, the easier to remember.
2. As is commonly pointed out, there are a total of 17,576 3-letter combos. They are rare, and a large number of the 17,576 3-letter .coms reside in the hands of end-users. Thus the remaining "available for sale" 3-letter .coms are limited, and any interested buyer for any of these remaining names will have to pay a price acceptable to the domain owner to get their desired domain. As more and more 3-letter domains fall in the hands of end-users, the supply dwindles, and even if demand remains the same, this usually equals a continued rise in prices (at least on the wholesale level) for the remaining supply.
3. Given that our society does think commonly in abbreviations, most 3-letter .com domains tend to get natural type-in traffic. This traffic can vary greatly, but somewhere in the numbers game, traffic usually equals $ return in the PPC arena. In this way, the traffic and ppc income can then function as a "dividend" for the holder of the domain.
There are perhaps many more reasons for the continued rise in 3-letter .com domains (along with the other 3 Letter Gtld domains). Michael, your points are well taken. I'll admit my bias in my response, but I very much enjoy the debate on both sides.
Thanks again,

zesty