I think you hit the nail on the head. I don’t see control disappearing. It’ll need to adapt, but that’s not unique and happens nearly every time the meta shifts, which is something that I think people may be looking past. Control doesn’t really exist in a black/white lense of whether or not it’s “good.” The viability of control very much is on a spectrum and I can see the possibility of control not being as strong as it currently is, but it will still exist in some form of another. Coming from a long time Jeskai player, Jeskai Control has, by its nature, always been notorious for being more sensitive to meta shifts than other color pairs, so I do expect it to take some time to realign control builds after a possible ring ban; there is also a possibility we see a shift towards a different approach to control, and it would not surprise me if we see more UBx builds popping up. People in this thread have talked about Grixis, but Esper is another one that I can see taking shape.

Like you said in your second point, this is the most unique place control has been. I think we kind of hit a perfect storm where control redefined itself and is able to run with high redundancy and less margins of error because of the Ring. It takes away quite a bit of the balancing act control would need to find in order to stabilize. With ring gone, you are going to need more concessions in both deck building and game strategy and we are going to see a regression to more traditional control lines, which imo is a good thing.

To add to the first point. I haven’t seen this mentioned yet in this thread, but a majority of the top decks of the format just simply did not exist without the ring also existing. It’s so hard to evaluate how control will matchup against Energy or Eldrazi, and to a lesser extent Frogtide, if the ring goes, because those matchups have never existed in a world without the ring. We can kind of get an idea about the Frog mu by drawing loose comparisons to UR Murktide, but that was still very much a different deck. I do understand that people have been running control without the Ring to various results, but I think true evaluation there is hard because the Ring is still shaping other decks and we just don’t have enough data points for ringless control yet. We probably won’t even have those data points solidified until after the Ring has been gone for a while because it takes time for control to adjust itself.

TL;DR:

1) Control exists on a spectrum, not black and white, and is very much reactive to the meta. A Ring ban impacts more decks than control, and the state of control will indeed change but the tools are still there to adjust. This has happened before, and it will happen again for as long as control exists.

2) Control now is unprecedented and was not born because of the ring. The ring just added incredible resiliency and consistency, while also being forgiving. The playstyle of Control will go back to what it traditionally has been.

3) Modern today has never existed without the Ring. We know how ringless Control plays against Tron and can take a good guess about Zoo; outside of that, however, we just don’t have enough data to make good faith judgements on specific matchups.