Did We Hit the Limits of Genetics?

I know it is a long way till harvest is over, but I think I might be seeing a trend.  Yes we all seem to be enjoying high yields to one extent or another.  On the other hand, I was able to glimpse the yields on a variety check plot in the county.  Yields varied a good deal from one variety to the next.  The high was something like 283 and the low was around 230.  That seems like a wide gap especially in a year when growing conditions were excellent if not perfect.  I have heard similar situations from individual fields where the biggest difference was variety.