There is no rational explanation for this, because with such a high price of CD players, the use of more expensive AKM or ESS chips is not justified even from a marketing perspective?
And in cheap devices costing $300-500 it is so exposed.
According to the AKM specification, AK4499EX can be used in CDs, but manufacturers don't do it - I don't know why.
This example from RME ADI is good, there are some videos from the manufacturer and he explains it there.
It is true that the latest chips have achieved abstract decoding capabilities of up to 1536kHz sample rate, currently there are no recordings at such a high sampling rate.
It may seem that on paper see link
https://audioxpress.com/news/akm-ak...ship-d-a-converter-solution-enters-production
It's great and simple, but good implementation in devices is difficult to do.
A good example for DAPs A&K SP3000, Shanling M9 PLUS, HiBy R6 Pro II - apparently the same DACs AK4499EX and AK4191 are used, and even ignoring the amplification stage and using only LineOut - the sound is the best in SP3000 because it is a well-thought-out, technically advanced design.
I also used AKM devices for many years - I omitted ESS chips, it was more because I was used to AKM.
I was looking for a DAP with large isolated ,dedicated ,output options: PO, LineOut, PreOut.
I bought the latest
A&K Kann Ultra DAP on the new ESS ES9039mPro chip,
even using it only as a DAC via LineOut for an amplifier, the sound is amazing, much better than cheaper models, e.g. HiBy from AKM.
In my opinion, it's a matter of the design of the DAP, not the chip, because A&K SP3000 is also used on LineOut with the AKM 4499EX also sounds magical.