Below is a graph showing the references, by year, to the words "Joseph Smith" in general conference talks. The graph below shows references to Joseph Smith by year in general conference talks. The graph below that shows occurrences grouped by decade. The blue bar shows the average number of references per year, and the green bar shows the range of references in that decade (min to max).
Looking at the overall trends, it looks like there is a dip around the '90s as compared to other years. However, there is quite a bit of variability from year to year, and it would be hard to say there is much more than an average 20% de-emphasis on Joseph Smith at the low point (incidentally, references to the Book of Mormon were increasing in that time period).
My friend and I could probably have a lengthy discussion as to whether or not this is a significant trend. However, I'm sure we would agree that regardless of the decade, Joseph Smith and the restoration of the gospel are foundational doctrines for the Church of Jesus Christ of Latter-day Saints. Even at the "low point" in the '80s, Joseph Smith was at the center of several talks, such as this one in 1985 by Elder Rex C. Reeve.
I am grateful for the prophet Joseph Smith and his role as a modern-day prophet. His words, actions, and life testify of Jesus Christ and were instrumental in bringing the fullness of the gospel of Jesus Christ back to the earth in our day and time.
