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.