I didn't stop to think that there might not be too much demand for such specialized work. Eventually the copyright impoundment cases dried up and I had to rethink things. Rethinking things is a fairly regular function of the sole practitioner. The point is that you can wait for a long time for the next big check from the big case, when you could be getting a lot of little checks from smaller matters. Nor do their friends.
Business people are usually too practical.
Even someone who gets into a lawsuit once probably won't do it again. There are exceptions, of course, but as a general rule, litigation does not reproduce itself. But once it's over, it's over. That is why it is difficult to build your solo practice around commercial litigation. Because It Won't.