In case someone is not aware, this is the feature request to vote on:
Personally, I think I have kind of made my peace with it, after being quite vocal about this, mainly because I didn’t see a good way to get internet to my wired Rock if cable internet is out.
However, prompted by another forum post about this, I have figured out that my Fritzbox 6690 lets me USB-tether an Android phone, and will then route over the phone’s cell network. This takes care of my personal issue, unexpected outages of unknown duration, and it’s actually a good solution not just for my Rock but for the whole network. (And I just got an unlimited data plan for ARC). Maybe your router has such an option as well. Or you can try with a USB wifi dongle on your NUC/Nucleus, then use the phone as a wifi hotspot.
Nevertheless, I still think that this is going to come up for a long time, whenever someone has an outage who was not aware of this - and I think there will be ample supply of Roon users who aren’t, for a long time to come. So, if I was Roon, I would be looking into implementing a simplified fallback state where you can at least list albums and play music for a few days. But I’m not Roon.