If you have a high quality DAC 10 years old chances are it will still sound excellent today. Maybe when it's measured on a machine newer DACs might have better specs but the human ear won't be able to hear it. DAC chip chasers remind be of kids at Best Buy searching for the newest Gamer laptop. In my Game Room I have MC275, C2200 LuminU2. My DAC Prima Luna Tube EVO100 It uses Burr Brown pcm1792a chip which is 22 years old. It's an amazing DAC and still in production today.The DAC isn’t upgradable on these streamers, because in order for the the streamer to be certified by Apple, Samsung etc, they need to certify it end to end as a complete system. A replaceable DAC would mean it couldn’t be certified.
This is why the streamers have fixed DACs. This has been mentioned a few times by Ken Zelin, who was let go by Bose and no longer with McIntosh