Because many programmers are not in the website business. I'm a scientist, working with long-term simulation models. My problem is trying to find a good model representation of the data that I observe. I keep my eyes open towards probabilistic relational programming languages (such as http://www.openbugs.info ), but so far I haven't found a way to apply it to my work.

Lisp is useful to me (more useful than ruby or C was), predominantly because I can work with emacs/swank/slime and change and query my program while I'm observing its output.