Thanks for turning this into a poll... it'll be interesting to see the (albeit unscientific, haha) results from a group of hardcore sports fan. There was a more scientific poll (although with a small sample size for such polling) that seemed to reflect how "split" the public is on this, although it tried to sample everyone rather than just sports fans.
I voted and made myself be realistic, as opposed to aspirational... which yielded an "early 2021" choice. I will never have been happier to be proven wrong if things start earlier. But everyone here has done a great job of highlighting the various challenges we face (I won't rehash them), and I think that realistically we're farther away from those things happening than we like to admit.
The other thing that we haven't talked as much about is the human side of things: how much risk will not only the players, but the various support staff, and finally the fans, be willing to tolerate? Even if we get to the place where we do have the large-scale and rapid testing that we all seem to agree that we'll need, there'll probably be a delay period after that until people are actually confident in those measures. And that doesn't even take into account the policy/bureaucratic nightmare that could ensue. For instance, if there's any chance for people to start attending sporting events in 2020, I imagine there'd have to be some sort of system in place to "validate" that people have tested negative for COVID immediately before attending the event. But there are a lot of Black Mirror-esque consequences that could ensue from the creation of the infrastructure necessary to do that. What type of risk are people willing to tolerate on that end as well?
That's why I went pessimistic in my answer. I hope against hope I'm wrong. But even if we operate under an optimistic perspective on the scientific side of things, there's also the "human nature" side to take into account that will probably lead to the time frame being longer than just that suggested by the science.
As a side note: let's imagine that CBB doesn't start until Winter 2021. That would suck. But it could lead to some very interesting and creative solutions. What if there was no non-conference games, but an expanded conference season, to make things easier to plan and also minimize travel? How intense would ACC games be when you knew your post-season aspirations could realistically hinge on every game?