Adam Connor brings up the most common reaction I see when a non-mainstream language is proposed:

They do care about price (including long-term maintenance), but there are a lot of other considerations. A brilliant Lisp programmer may produce a more effective, maintainable solution 1, but what if he leaves? Hiring Lisp programmers might be tricky, and thus entails risk. Moreover, most businesses would rather hire a strong business analyst with so-so programming skills than a brilliant programmer with so-so business skills. The reason is simple: the business analyst will produce a pedestrian solution to the right problem, whereas the brilliant programmer will produce an elegant solution to the wrong problem. Or so the thinking goes; of course, the ideal is to get someone who is strong at everything, but they are scarce and priced commensurately.

Seems that learning a new language is a nearly impassable hurdle, at least in the minds of a lot of the industry.