I hope those folks who have been in the market for a very long time can comment on what I am about to say. I was thinking about this data and if this data is correct, the NEW drum set unit sales have gone down in US.
However, isn't this period between 2005-2014 the period that the internet listing of the USED drums started to flourish? Isn't this the period that more people started to trade on Craig's List, Facebook, Reverb, and Ebay instead of buying NEW? So, perhaps the NEW drum set sale has decreased, but the USED drum sales have increased in US.
Also, when I went to the NAMM 2024 show on a Friday, the foot traffic in the drum section was light to medium. However, the Guitar section was very crowded. Perhaps these days, there is a whole lot more interest in Guitars and Keyboard instruments than Drums. So, that may also explain the downward trend in NEW drum sales.