I thought it was a good read also. However, I'm not sure that the premise is correct.
*Disclaimer* I have no market research or special knowledge of the market for musical instruments. But I have done a lot of work in interpreting and understanding market dynamics backed by market research.
They are probably correct that there is a general slow down in the sales of musical instruments. But I don't think they really know what is causing it; they don't talk about any market research to quantify what is happening. It appears to be their own guesses/gut feeling.
As much as there may or may not be fewer kids buying guitars, kids tend to buy cheap used stuff. The market for expensive gear is middle aged people; people that have careers that support expensive hobbies. Those people also have to worry about making mortgage payments, sending their kids to university, and preparing for retirement. So as much as the economy recovered from some significant shocks between 2007-2012, a protracted period of economic uncertainty had a longer effect on their target consumer. Those people having very recently looked into the economic abyss likely want to have a bigger personal safety net; possibly not having had one prior to 2007.
Have a number of people made some big blunders? Absolutely - the Gibson auto-tuning was a dumb idea. But that gives me confidence in my thought that they probably do little or no market research to understand their target audience. So as much as the major names that everyone knows may be struggling, there may be many smaller manufacturers that are picking up that market share. @Dadagoboi perhaps you can shed a little light. Without getting into any specifics, what sort of growth/decline are you seeing in sales by dollars and units over the last decade?
Or put another way, are people that might have bought a Gibson TBird now buying a Cataldo?