I think ultimately I have two main points:
1. These types of trades are rare and difficult to make. Of the 18 names you listed, only 3 got traded here in basically the middle of February, and all of them only had one year of control left. That's not a Hoyer problem, that's every team not trading for these dudes. The Burnes trade is a good example, one year of a (very good) starter for basically a Matt Shaw/Assad package. Would you do it? I can see the argument: makes us the favorite in the division for this year, every year is valuable, etc. But still doesn't put us anywhere close to the Dodgers or Braves, and a year from now we'd be down Shaw, Assad, and Burnes.
2. So if you accept that there just aren't trades happening for quality players with years of control, the only place to add that to your organization is the Boras four. All quality players, but really the only one with an 'elite' argument going forward is Snell, probably the guy we talk about the least on here. There's only so many times you can pay a market premium for non-elite talent before you hit a ceiling. You want a $65m outfield locked in where none of them are likely to exceed 4 WAR? Where you turn PCA, Alcantara, Caissie, etc into platoon guys or trade bait in the mold of Michael Busch, where everyone knew that the Dodgers didn't have a spot for him and we got to basically pick up a AAA top 100 dude for a single A top 100 dude? Like, ignore Ricketts and the luxury tax for a second and slot Bellinger, Chapman, and Montgomery into the roster on long term deals. That's a very solid, 88 win team. How does that team get better going forward? Where do we upgrade? Outside of unlimited budgets, it's almost impossible to become an elite team without your system turning out some studs. Jeopardizing that to turn 81 into 84 seems shortsighted.