The main reason that I believe people still pursuing Beale’s treasure because of the obvious reasons:fame and fortune. The allure of millions of dollars worth of gold laying 
around somewhere in Virginia is just too strong a temptation for most people to ignore, and those with the means and drive to actively search for it are going to because for most people, the outcome of finding the treasure is worth the effort. In addition to the monetary value of the treasure, claiming the Beale Treasure would result in fame across the country, the person that solved it would hailed as a modern Benjamin Gates (National Treasure, Nicholas Cage). The temptation of these two strong drive forces are powerful enough to get many people started, and the sensation that they are on the verge of discovering the treasure, much like the sensations a gambler feels when he hits a rough patch in his betting, is what keeps them at it.
Abbey
While reading Singh’s narrative of the Beale Cipher in The Code Book, all I could think about was the movie National Treasure. Herbstts says here that anyone who cracked the Beale Cipher would be “hailed as a modern Benjamin Gates,” but the more I thought about it, the more connections I saw between the two stories. The second letter of the Beale Cipher was decrypted using a book cipher, with the Declaration of Independence as the key book. A mythical treasure worth millions that many people don’t believe exist, and the Declaration of Independence? I can just see Nicholas Cage getting excited about tracking down Beale’s gold. In the movie, a code written on the back of the Declaration is decrypted by using some historical letters as the book key, but it is a very strong similarity. The writers of the movie could have easily picked any national document: the Constitution, the Bill of Rights, etc. But I think the use of the Declaration is supposed to remind people of the Beale Cipher, the real life national treasure that has yet to be found. And it makes me wonder, would it take a “modern” Benjamin Gates’ courage, adventure, and what some might call stupidity, in order to finally crack the cipher and find the treasure? Maybe someone wanting the fame and fortune will come along, someone just crazy enough, to make the breakthrough and discover the gold.
Derek
Or, perhaps, like “National Treasure,” the Beale cipher is a work of fiction!