I think we almost agree in many ways on this with but there's a few things that make me hesitant and makes this too unknown:
1. HBO Max is a huge priority and as of late there have been different signals on what WarnerMedia wants and will do vs WB.
2. Home sales of many of the films have been strong which is the best indicator at this time of possible people who would be interested.
3. Adding on from my first point, HBO Max can do what it wants and WB can do what it wants thats what throws the biggest wrench in this. So if hypothetically, WB does not move forward with Henry Cavill as Superman then HBO Max has the opportunity to pick it up if they want to. From a streaming service standpoint picking up the current DCEU wouldn't be a bad buy. Im stating this when I compare the content that's on Netflix and Amazon. The DC films were not big in comparison to Marvel but the majority did not perform bad. With that being said, lets say that JL does as well as a $300-$400 million dollar movie in streaming numbers, does that prompt a sequel? Its hard to say because streaming service metrics for success are different then the theatrical release metrics for success. But my guess is that the success criteria for streaming is less than the success criteria for theatrical which could benefit this film.
4. Snyder doesn't have a bad relationship with HBO Max yet. WB relationship is blown to shreds though.
Its way too hard to call any future for DC because of HBO Max now and the parent company's extreme interest in making it popular and getting subscribers.