Manufacturers past their heyday

No highs? No lows? Must be Bose!

There are several factors at play here. One, many of these legacy companies have been absorbed by big conglomerates (Mark Levinson, McIntosh, Harman Kardon, and Martin-Logan come to mind immediately) so they're no longer driven by a few brilliant guys passionate about delivering the best audio possible, regardless of how much profit they can squeeze out of every unit sold. (And, a lot of the legends and pioneers of high-end audio are no longer with us, Those geniuses were the drivers of their brands. Without them, many of their brands are shadows of what they once were.) Two, audio technology hit a plateau years ago. There's only so much audiophile-worthy innovation that's coming forth nowadays, unlike during the golden age of the 70-90s. Three, digital. Streaming audio has more or less killed the notion of audiophile sound. Convenience over quality. Then again, it has driven the vinyl renaissance, so there's the silver lining.
 

PS: Pioneer???

I remember many years ago, I got into Steteo Exchange in NYC and listened to a pair of Mirage M7 bipolar speakers. They were great. 

One good news story - Luxman. Got bought out by Alpine in the 80‘s I believe and rapidly went downhill. Not sure what happened after that, but they appear to have risen like a phoenix to attain their former status.