This doesn't have to be a fire sale. In fact, pulling off a firesale with this roster would be quite a feat. There are a ton of long- or mid-term assets and moving all of them would be a challenge.
What Hoyer needs to do - and I think this is the point of the article - is accurately judge which players should be moved to improve the club long-term. That's not all of them. It might only be one of them, though it seems Hoyer should aim higher than that low bar.
Teams can sell and compete the following season, they just need to make the right decisions and be aggressive with their choices. The Cubs have many players with value in trade and as the roster is currently constructed, they're somewhat expendable. Make the right choices, pick the right guys, and this can be an on-the-fly retool.