MHO...
Class D has already surpassed all else in terms of 'units in service', if you count cell phones and any portable digital device. As for the quality, it'll turn on demand. What with the rise of headphones and ear buds, that is what will ultimately 'push' the market's response. 'Home theater' will benefit from that, and will add to that demand. Smaller, more powerful, better response will prevail. All else will eventually become 'niche' or 'vintage', which is already occurring.
Digital will win, analog will fade, becoming the 'start' but not the end product.
'Analog' will be what you experience at a live venue, instantly becoming digital with the means of amplifying it or recording/reproducing it. Is mostly thus already...
'Flat panel' speakers are another subject we can dis about and over... DML's are beginning to be less laughable already. Why would someone want an ugly or even stylish 'monkey box' cluttering up their already small living space when they could have this 'picture' like object hanging on the wall that sounds great 'enough' and a subwoofer is the coffee table?
As J. Lennon suggested, "The war is over." The new will replace the old over time, as it always has.
Unless you'd like to get rid of that nice UHD flat panel TV you've got, and go back to CRT's, I'll suggest that y'all get used to the future. It's here already, becoming the past as we sit and bitch about 'change' and how we may not like it...
Or, to be really crass about it....it's 'vintage' already. Get Over It.