We could but it would be difficult. Our product requires that our customers subclass our Java classes to implement their custom business logic, and sometimes it's necessary to provide the source to our base classes for reference. Sending a customer some Clojure code and expecting a Java developer to know how to handle that doesn't seem reasonable.
one can also ask the question whether its you that want to continue coding in java, because you think in java, or because you want to avoid learning something new. But yeah, if the customer don't grasp Lisp, you are pretty much settled with java.
If one were to ask me that question I would respond by saying that I have been programming in Common Lisp for many years and would gladly switch to any lisp, especially Clojure, if it made sense for our business.