The idea that there's an inverse relationship between how much someone thinks they know about a subject and how much they actually know is pretty timeless. When people refer to Dunning-Kruger I take it to mean shorthand for that phenomena rather than a reference to results from a specific study done in 1999.
I may be misremembering, but when I first saw references to it on Slashdot, etc., it was from people reacting in amusement that someone was able to quantify and measure what seemed like such a commonly experienced aspect of human behavior. If someone had done an academic study on the increased likelihood of friends having scheduling and availability issues around weekends in which one friend was moving to a new house but was too cheap to get movers despite having plenty of money to do so, it would've gotten a similar response. :)
Since then, it's just been convenient having a name ("Dunning-Kruger", that is) for a concept that was widely understood but didn't have shorthand for referring to it. I'm not surprised that the study itself wasn't definitive and airtight.
I may be misremembering, but when I first saw references to it on Slashdot, etc., it was from people reacting in amusement that someone was able to quantify and measure what seemed like such a commonly experienced aspect of human behavior. If someone had done an academic study on the increased likelihood of friends having scheduling and availability issues around weekends in which one friend was moving to a new house but was too cheap to get movers despite having plenty of money to do so, it would've gotten a similar response. :)
Since then, it's just been convenient having a name ("Dunning-Kruger", that is) for a concept that was widely understood but didn't have shorthand for referring to it. I'm not surprised that the study itself wasn't definitive and airtight.