Class D has now matured.Its obvious that this statement is false. '2018 amps are so last week; only 2019 amps can be considered.' is the message I'm seeing here. I can point out the exact post if needed.
We have a patent pending on how to eliminate the need for dead time in class D amplifiers. Now if a little guy like us, previously unknown for even a solid state product, can make an important contribution like that (dead time is one of the major sources of distortion in a class D amp) then its pretty clear that class D is not a mature technology.
Innovation S-curves start with lots of time and money poured into the tech with little to show for it; as it gets sorted out the tech improves dramatically with far less time and money invested. When the tech is mature large amounts of time and money are needed to incrementally advance the technology. So its very obvious that class D is not matured.
Class D isn't there yet, but its obvious that if the designers can get their collective heads around what is important to the human ear and what is not, then we will see something that really is an improvement and by that I mean something that may well be better than tubes.