Yet another high-end class D amp

[E-Stat]

Anyway Levinson talks about their proprietary technology ...

I suspect that what's really different is addressing the bandwidth limits of the power MOSFETs. Since the modulation occurs in the analog world, the outputs are now dealing in the AM band.

...the 42x price tag might be an example of hyper-diminishing returns.

Or recognizing the potential of the concept. Similarly, I find there is nothing inherently wrong with digital recordings - the limitations are shaped by the frequency and word size decisions. I find a parallel with switching amplifiers. Getting the filter noise further out a couple of octaves is a logical progression for improving the technology.