Class D is like Bluetooth or USB--a licensed technology that must adhere to certain standards and chipsets
This statement is 100% wrong and apparently poorly informed. Class D is nothing like Bluetooth or USB other than in someone’s mind apparently.
Class D is a design approach. Anyone can try and build one anyway they choose
It does often but not always involve popular modular designs or a board/component that can be used to build a complete amp product.
The reason certain modules are popular are because they are the product of a lot of modern technical innovations done well ( as a result of years of R&D) and therefore THEY ARE VERY GOOD ie they do the job very well and often for more modest cost.
Not to say everyone will choose them. That is never the case. Personal preferences always rule in the end. Some simply may not believe that technology always moves forward but in fact as a whole it always does.
Glad we cleared that one up. 😉