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

As others have said, class D is now quite good, and for the majority of users it probably delivers the best value when taking into account sound quality, size, heat, weight, etc. I've got a pair of DIY Purifi monoblocks that sound excellent. 

But, I recently acquired a pair of Pass XA60.8 monoblocks, and there is something about the sound that is captivating beyond what the class D amps can deliver. I'm sure there are tube-fans that would say the same about their amps. 

I don't think my Pass amps are any cleaner, more dynamic, or more detailed than my class D amps, so there is something else that is influencing my satisfaction. Perhaps it's minor tonal changes, or distortion harmonics, or maybe I just like a slightly warmer room :). 

But whatever the reason, I think there will continue to be different options to produce different sonic signatures, since everyone's perception of reproduced music, and preferences, are a little different. 

I do think class D will eventually dominate as the value leader, but there will always be audiophiles that have enough money to buy what most appeals. This may shrink the market enough that there are fewer choices, but I don't think they will go away any time soon. 

I have had some good class D ,I still feel a very good class A, AB 
sounds more fluid .I hav3 a Coda CSIB integrated  and it has much more. Control ,and depth of performance IMO. Spotted 3,000kva transformer ,and over 80k uf in capacitance  runs in pure class A for almost 20 - 1st watts and pure class A preamp ,even my dac runs in pure class A on the analog outputs  I am good with my Amplification I think it just has more depth, some class D like Merrill sound very good but Waay over priced ?

I had a tube amp in the late 60s/early 70s (HH Scott 222c, still have one), a Sony TA-3200F (first 'super amp', still have it) and multiple others. Now I find myself using a number of TPA-3118 based class 'T' amps (D with a few mods as you know) since I have a 4-way with a mono sub, requiring 7 amp channels to quad-amp (rest of the system is on 2 desktop computers). They sound incredible and eat hardly any power, not that I focus on the latter. My only concern was phase effects on the tweeters, what with the RF filter, but since I correct measured phase deviations on the 'crossover' computer's filters anyway it doesn't matter (and there's hardly any anyway). Scoping tweeter waveforms requires some amplitude to overwhelm the residual RF (rough on the ears) but that's the only drawback. Sound is crystal clear, and it's amazing to see tiny chip amps driving big Altecs and horns (though they're exactly what they should be driving, being efficient). Big speaker doesn't mean big amp.
I see/hear nothing with these little amp boards that's inferior to what I've seen/heard over the years through my heavy, hot old amps, which I still love. Quite amazing really.

"Rocks might melt, the sea might burn."

It'll be the end of the world as we know it.