Reddit mentions of Harmonicas, Harps and Heavy Breathers: The Evolution of the People's Instrument

Might I recommend that you read the book Harmonicas, Harps and Heavy Breathers: The Evolution of the People's Instrument by Kim Field? This well-researched book will give you a deeper and broader insight into your question than the random observations of people citing their own favorites within their own specific area of interest. Originally published in the 1990s, it may or may not cover your still-undefined period of "modern," but then, that may also be true of the responses you've received here thus far.

By the way, I'm also curious about your use of the phrase "harmonica industry in the USA." There has never been significant harmonica manufacturing in the US aside from a few desultory attempts, so there has never been a US harmonica industry in that sense. There are, of course, importation (from Germany, China and Japan) and the resultant wholesale and retail distribution. There is a cottage industry of people making products to service harmonica players - upgrade parts and customization services, repair tools, microphones, amplifiers, and other accessories. There are clubs and organizations such as SPAH that promote the harmonica. In the recording industry the harmonica is one of many instruments employed, and a minor one at that, so I'm not sure that this would fall unde "harmonica industry."