I'm not quite understanding. There have been some decent products coming out of the Harman groups. Perusing Amir's speaker ratings, a fairly objective measure, I found 12 out of 60 speakers (20% or 1 out of 5) in the top rankings. I don't really dispute that there has been some slippage in their speaker quality. Revel which makes up most of the highest rated Harman speakers has not come with a new model in 5 years or so except for an in wall model. It seems like it may be phased out at some point like Infinity which also had several high rated models in Amir's tests. It seems like as time has passed they've strayed from the Floyd Toole/Todd Welti/Sean Olive research into sound reproduction. Some of it is the usual problem of a too large company that loses it focus and also that other companies have caught up in some cases surpassed them such as KEF.
considerations:
1) there are 7.8 billion people on earth and, if the audiophile group reaches a few tens of thousands of people, that's a lot. The bulk of the market is made up of: portable devices, non-audiophile headphones, sounbars, Wi-Fi single speakers.
2) much of the audiophile market, given the prices, is based on second hand.
3) there are two types of companies: those that produce new products continuously, often identical to each other, and those that produce few new models, but each one is well thought out.
4) fashion factor of the brand: every year we see a brand that becomes over-advertised, which perhaps hits a range, and then everyone must have that brand. Then clearly after a short time they forget everything
5) Jbl is famous for its production 40..., clearly not everyone has a dedicated listening room, therefore these speakers with such shapes do not always fit into the living room of the house. Nowadays, lacquered, discreet and small speakers are the most popular, which go well with the bookcase and the sofa...