You are obviously more plugged in than I am. That Springer and Indians thing was at least a conversation in 2016, right? Did they get so far as to have a meeting or work up numbers on a return?
I don't remember the Indians specifically as that was over three years ago. I do know the Astros had gauged interest in Springer prior to 2017 and they were looking for starting pitching. Sometimes trades happen (the Astros discussed Greinke with the Diamondbacks starting the night the Astros were eliminated by the Red Sox and it happened many months later) and sometimes deals never happen (Astros thought they had a shot at Stanton at one point). I expect a lot of discussions this winter with the Astros talking about a lot of players that are fan favorites, just to gauge interest and to see if there is anyway they can maneuver to keep Cole and overall be a better team.
Part of the problem with shopping star players like Correa is the human element of the team. If you don't get back another established star, you are going to have a very upset clubhouse.
I'm not going to say that the clubhouse is full of a ton of strategic and long term thinkers, but I'd like to think that if that came with an extension for Springer and a legit offer for Cole that the FO would have built up enough equity in the clubhouse that those guys would understand.
Players don't see it that way because it is just money for extensions. If it were a direct trade they'd be alright because you have to give talent to get talent. Saying that I do support moving Greinke if it meant we kept Cole. Other players also aren't too concerned with other player's extensions. Verlander is 36. Greinke will be 36 next week. They are also only under contract for 2 more years. Same as Correa (aside from Correa being arbitration eligible than actually under contract).
I think Morton is a good example, though. The Astros' clubhouse loved him and the front office let him leave and didn't replace him with anyone, and everyone seemed to understand. They let Keuchel go without making much effort to keep him and same thing. Those aren't trades, but they are effectively the same as trading guys for nothing. I think the Astros' clubhouse all know its a business and since they all want to eventually get paid too, they probably understand the team's going to have to make some tough decisions every year.