fish1050
Headphoneus Supremus
Well, it's obviously a matter of speculation. Your points are well reasoned, but it's based on speculation. The truth is, only some people at Sony know why they took so long to enable AptX (and AptX HD) on the WM1Z/A, and I think your guess is a pretty good one...
...but it could also be that we don't know about some deal Sony made (formally or perhaps informally) to enable AptX on any current players that have the chip, and the A30 series, in the US, is still a current version.
It is strange that the A10, A20, and now the A40 have AptX, and yet the WM1 did not, and the A30 series still does not, given that the WM1 and A30 came out in the same year -- it makes me think that given their history supporting AptX (and so obviously having the chip) and the WM1 getting AptX later, and thus proving it at least had the Qualcomm chip all along, that it's highly likely that the A30 series has the chip, too -- but I'll agree that it's unknown as to whether Sony thinks its necessary to enable it or hope it drives up sales of the A40, but I tend to doubt the latter, myself.
It's not like the A40 series is even readily available in the US, either. I did a search for it and found only a few places to even purchase it, and I'm not even convinced that any of those selling are US versions.
B&H still lists it as "pre-order." Accessory Jack is selling the Asia Pacific version.
And Sony itself, when you click on "Where to Buy" from the official product page, returns this sad, sad message -- granted they kind of stink at listing online retailers with stock, but my own independent search yielded nothing from major retailers, including those who still carry the A30 series (and sometimes even the A20 series):
https://www.sony.com/electronics/walkman/nw-a40-series/buy
EDIT: if they decided to enable it across the line (which would just leave the A30 series out currently), it's no surprise to me that they would first do it for the WM1, since that's a flagship, so that would explain to me why they haven't released it for the A30 at the same time.
My post isn't based solely on speculation as I had the opportunity to talk with a Sony sales rep on two separate occasions and heard two sales briefs. The first time was a couple of months after the A30 series was announced. The sales guys who were in the briefing were curious about AptX support on the A30 and why it was left out. Several customers had inquired whether it would be added at some point. The response although somewhat vague pointed to Sony negotiating with other manufacturers to license LDAC at a very cheap price. The gist was Sony wanted to highlight the LDAC codec on their 2017 models and initially felt that leaving AptX off would get more people to try LDAC. As to whether AptX could be activated on either the A30 series or WM he would not commit either way. After the briefing I had a chance to talk to him for a few minutes. I told him I was interested in the A35 but only if AptX would be available. He said to the best of his knowledge the A30 series was not capable of adding AptX. It was after this talk I chose to skip the A35 and wait for the A40 series.
The second opportunity was a sales briefing after the announcement of the A40 series. Once the sales rep confirmed that not only would the A40 series support AptX but also AptX HD with a later firmware update I knew the A45 would be my next DAP. Again I had a chance to talk to the rep alone for a few minutes and asked about Sony's decision to once again support AptX and AptX HD. He said he was not privy to all the details but he hinted that Sony's desire to get LDAC support on third party devices was partially contingent on Sony also supporting AptX and AptX HD on their devices. Basically no other manufacturer would support LDAC without also supported AptX and or AptX HD.
As for the WM series and AptX support I wasn't considering that model so I didn't really care if it supported AptX or not and never inquired.