It's standard procedure to move guys at the deadline when:
a) the team is out of playoff contention
the player's contract is expiring
You'll never be criticized for moving guys under those conditions.
And your closer has given up 3 devastating home runs in the last 5 postseasons (one of which was survived by the Cubs).
No other closer in history has done anything like this.
That's not the only reason we don't have enough starters.
The Yankees are in much the same situation with Kluber and Taillon.
They just have a lot more depth than we do.