Expert Systems of the past had user interfaces, though crude ones such as Java applets and basic HTML forms. UI evolves too fast and new means of HCI emerged like VR/AR, IoT, etc. Most likely the human interaction will have to be made by humans, but the more fundamental advancements can and will be automated. Being a "front-end engineer" on whatever platform, be it web, mobile, embedded, seems to be a pretty stable career in the future, at least for now.
Nope, drools [1] is a Java Expert System. It's fairly old now, but it's maintained and advanced.
Heck, I used PHP to interface with CLIPS [2] to provide a simple suggestion engine for a college project back in 2002. It had a simple wizard flow where it would ask a few questions, shell out to CLIPS for the next series of questions, do that for a bit, and return a suggested product.
