Class-D has a long history, but around the 90s, the amps people were making were terrible. In the 80s they were used to save battery power, physical space, or heat buildup. They were basically motor driver circuits modified for higher frequency. Most were only sub amps or mid-fi car amps.
When I proposed a high fidelity Class-D amp at my job, they said there’s no market for it. This was late 90s, and they licensed technology I previously developed while putting me to work patenting my direct digital amp designs. I told them there is an inherent performance limit to this type of amp, and they said performance doesn’t need to be all that great, but cost is the #1 concern.
Around the same time, a few audio companies came out with Class-D amps, and the first ones sounded awful, had real problems with noise, and barely made it to 20kHz. That gave Class-D a bad reputation.
Also, there is a common misconception that the D means digital, but that’s not true. Class-D simply means “switching amp”. Digital audio already had a stigma, adding to the push against Class-D. There are also many variations in circuit design to make a Class-D amp. Most amps on the market use the same old techniques that were used for Class-AB combined with simple switching tech from power supply designs. The result is that very few designs can really control speakers well through the entire audio range. I could go on and on, but the market is still resisting Class-D. Hope I shed some light on the issues. After 30 years of Class-D design, we’re still fighting the good fight.
Market driven concerns:
Many of today’s audio companies are getting squeezed, and it’s expensive to hire an engineer that can design high performance Class-D. Reference designs from chip companies are used by some, but they fall short of high end sonic performance expectations. That’s why so many turn to plopping a pre-fab module into a box and calling it a day. None of the long term commitment required, but this jacks up the cost due to the module maker’s markup, and almost every well known brand is already being pinched by overhead and now tariffs. Companies like Cherry Amp, where close to 100% of the product (chassis, wire harnesses, boards, misc hardware) comes from local suppliers, and technology is developed internally, stand to gain significant market share.