Class D amps seem poised to take over. Then what?

Nothing in the audio world from the 1950s is much more than an antique.  The 2020 something tech changes everything, including the functionality of Class D amplification.  Earlier in discussion someone suggested that putting a tubed pre-amp in front will make it all OK.  I now run a Peachtree Grand X-1 hybrid integrated with a pair of 12AU7s in the pre-amp section.  This is supported by 440 watts per channel of Class D transistors and this is a marvelous machine for a home system.  Smooth, able to wisper and bang a gong.  I do not believe most (any) listeners would be able to detect a real difference.  

Good for cars and woofers.  300 kHz and under switching speed very noticeable on a moderate resolution system in a poor listening room.  I have 3 class Ds on my sub-subs (3 kW) also in all the cars.  Maybe they will get better for a good system. 

Class D will most likely take over if you have inefficient speakers that take tons of power like Electrostatics.  They are great in large areas, sub woofers because they are powerful.  I have heard some class D amps and they do sound good.  For some people probably a good choice depending on the room, speakers, tastes in music. 
Most people probably wont notice much difference.  Not if you have really good Speakers that bring out the best and the worst in music with a side by side comparison.  From that point it is what you like to hear.
My notion for class D got soured badly when I made my first exciting investment with a combo Integrated class D amplifier, streamer. It was small, cute,  powerful. It was dynamic. I was using 45 year old Crown A-AB+ 90WPC Amp, Crown Pre Amp. 
The line that crosses between a good system and a high end system which varies greatly depending on what it is and the investment.
I was getting ready for that old equipment to have a good butt whipping!  Uh, No, not even a close comparison.  Where the Old Amps were getting the details, Low Dynamics in the Trombone, Tuba crescendos giving balls to the lows, the Class D failed to reproduce any hint of fullness of the true tones of the instruments. Only Bass, sharp toned highs. Could have been a mismatch of my titanium drivers. I have 8" carbon fiber woofers. There was plenty of power from the 60W class D.  In fact it had more loudness that the old 90W unit and the class D driving the woofers hard.  Just the details I look for in music were not there.

Then, I decided to go get the best I could afford.  I went with a Tube integrated and it is in a league of its own compared with the Crown.  Crown was good, but nothing like the Tube integrated at half the power. I have learned from a friend that bought a pair of Red Dragon mono blocks.  He said they were very good, but the Shiit Vidars in mono sounded better on his Magnapans. I will never give up my tube integrated until I am in the grave. I have had it 6 months and it just keeps sounding better. Jaw dropping sound, detail, enough to make you laugh, cry, and dance with the wife.  :)
 

Class D amps have gotten better without doubt. They are performing on a level never thought achievable. But as good as they are in providing great transparency, detail, full midrange (vocals) and deep mind-blowing bass they still fall short in delivering the emotional aspect of the music. Not tapping my foot anymore. Fix that and I might consider retiring my Class A/B amp.

The only thing a class D amp is good for is driving a sub. Whom ever suggested class D amps are good for driving a hungry watt eating speaker like electrostatics never had electrostatic speakers. Don’t you know how revealing electrostats are? Who wants class D when you’re better off with a space heater class A, or a 100 watt tube amp. No way I’m giving up great amps for trash.