Programming Language Theory has a public relations problem

Here's how to justify it: If you want to talk about something (program), you want the right language. We've got powerful languages capable of everything any computer can do, but new ideas often call for new ways to express them.

Building a language is about accepting massive up-front investment to build something that hopefully meaningfully improves user experience. Or you can build to learn about the inherent beauty of computation and formal languages, but I find that a little less compelling.