If you think that the Harper situation is irrelevant to the Cubs long-term thinking about Bryant, think you are wrong about that.
It would very hard for Cubs to be better by trading Bryant. Totally agree with you on that. But, Theo thinks Big Picture and I think he doesn't want to get to Nats situation of today, if he can avoid it. Every club, of course, has a different context but there may be ways to address this,who knows. One reason why Arenado's pending FA is interesting. Sign another terrific (albeit lesser) 3B than Bryant and trade Bryant a year from now for good stuff. Or, Theo being far more creative and knowledgeable than either you or me--do something else that didn't occur to us, at some point. And, you can encourage offers this off-season that might be more realistic a year from now. Or, two. Could be a long-term process.
As to Correa, if Astros do with Correa what Buster says Cubs are doing with Bryant, you'll want to hear about it--or at least Astros fans will want to hear about it.