I think it is reasonable, and I bet you too wouldn't mind paying $10 more for a better chip choice.
Yamaha's BD34703KS3 for volume control and other functions:
If you buy one of that chip, it costs $11.76, if you buy 1000, it drops to $3.92
BD34703KS2 Stock and Price by Distributor (findchips.com)
D+M's MSI chip for volume control only:
NJU72343
$2.89 for 1, $1.73 for 500
NJU72343V-TE1 NJR | Mouser
Overall D+M's cost would be a little higher, all else being equal, because that chip is for volume control only and will have to be used with several multiplexor/switchers, as explained in the HTHI article:
AVR-Audio Video Reciever-Build Quality: Part V - HomeTheaterHifi.com
View attachment 42764
Based on Dr. Rich's findings, "sound quality" in AVRs are likely determined (or limited) by the volume chip, not the DAC, and D+M appears to be the first adopters.
I know of at least one older Arcam flag ship AVR (Arcam seems to have gone backward on their recent models), had used the even better Cirrus logic chip the CS3318. That is the one I hope Yamaha will adopt if and when they are ready to switch from LSI to MSI for the import volume control.
That may be a tall order though, because the CS3318's unit price is $37.31, only down to about $24 for quantify of 1,000 or more.
Still, it is a very reasonable request for Yamaha to at least use the same MSI chips that D+M are using, but double the quantity for differential connection to the very nice ES9026 Pro that they currently are using in the CX-A5000 series.
As dealer, may be you can email them a link to Dr. Rich's article.
I think D+M made their upgrade has something to do with HTHF's 5 part series on AVR build quality but that's just my educated guest based on the fact that they had previous listened to him and upgraded the HDAMs once, started in about 2014/15 and appeared to have done again but limited to the SR8015 only so far.
The point is, detailed measurements by the likes of AH, HTHF, and now ASR do have influence.