1) in your own #s, then at the current price of 4.7BTC AM is still undervalued if it will generate 6.4BTC.
2) If you apply that type of reasoning to real life companies then you would rarely invest - APPL was likely never going to survive the 90s because its stock was overpriced right?
3) Buying AM is believing friedcat & Co. can do more with BTCs than you can. They might open new services or create new income streams (meanwhile reducing income seem unlikely.)
4) Txs, Txs Txs. By the time all Bitcoins have been mined, the transaction fees will make it worthwhile for the miners (Satoshi's white paper)

To be more detailed, ASICMINER has 200,000 shares in total. Each share gets
1/400,000 of the voting power of, and the regular dividends from, the Bitfountain
IC company registered in China.

Q: Why don't you use Bitfountain for your GLBSE ticker?
A: Because the ASICMINER shareholders (GLBSE investors) have an extra set of privileges upon Bitfountain shareholder (us).