It's the same in law and business as it is in engineering and science. The people who are determining the future through their research are communicating new ideas and advances to their students. They are also showing students how to operate in that future environment. The first and most important benefit of research is its intellectual and practical value. Research adds to the storehouse of knowledge and is used by the research community and by industry as the basis for other advances.
Research is the basis for technology transfer.
Commerce and industry rely upon the percolation of new ideas up through the research laboratory and into product development cycles. New ideas translate into intellectual property, patents and practical applications that are driving the world's advanced economies. Both undergraduate and graduate students learn about technology transfer in their laboratory experiences. IIT even has classes on creativity and product development. Research contributes to good teaching.