So, do you think Apple will market a dedicated unit, or are those of us who haven't got wi-fi capable entertainment systems such a small minority that we no longer count?
Unlike Microsoft, Apple has from the very beginning been intentional about dropping support for obsolete or unprofitable product and I suspect the Airport product line falls into the latter category. So I doubt they are likely to engineer and market a product with a market as small as you are proposing. If there is a viable market there are enough entrepreneurs looking for a niche surely someone would have stepped in to fill it. I did a quick internet search for network adaptors and although I found a lot of them and generally far less expensive than an Airport express the ones with a 3.5mm audio port were all bluetooth not WiFi and those that were WiFi capable only had USB ports. I also looked at network extenders and if they had an external port at all it was USB not 3.5mm.
There is no reason to believe the current generation of Apple Airport Express will quit working or become obsolete any time soon. They support 802.11a/b/g/ac and the WiFi protocol standards to date have include backward compatibility and are capable of IPv6 as well as IPv4. The only significant limitation is while they can
join a network created by any Wifi router they. can only
extend a network created by another Airport device and in your application joining a network is all it would need to do.
I am betting the odds are you would replace your stereo, possibly with a WiFi enabled device before the Airport Express would become completely obsolete. That leaves the possibility of electronic failure of the Airport Express or Airport Utility needed to configure it failing to run on a future version of MacOS or iOS.
If you want some security then you could go ahead and get a spare Airport Express. I have even seen them being sold as "Factory Refurbished" at a moderate discount.
