The common rube doesn’t understand jack shit.

Everyone has their area of expertise. "The common rube" at the hospital can be a professional cab driver who has half the city memorized or a sports buff who can tell you every significant baseball stat going back twenty years or a vagrant who has survived by mastering a litany of social protocols unique to the homeless population or a musician who has an entire arcane language for their craft.

As you specialize, you develop a jargon for the minutiae of your field. Which does go to your underlying point

Your research may further the understanding of a small group of people, possibly see some practical use, but the general public can’t directly make any use of it.

More broadly, they wouldn't have the opportunity to leverage the research productively. If you need an electron microscope or an industrial boiler or a large population of waterfowl to make practical use of a piece of research data, most people aren't going to be in the position to find it useful.

That said, expanding the pool of expertise is also supposed to be a major role of the academic system. If people in or adjacent to your field have trouble understanding your research output, it isn't easily transmissible to people who do have an opportunity to leverage it.

One of the reasons why you have these large populations of sports buffs and musical talents and cab drivers bouncing around is thanks to the improved mechanisms of education distribution. Finding a middle ground between specificity and accessibility is critical if you want to grow your population of specialists.