The Cubs scored the 5th most runs last year, and entered the offseason with the fifth highest-fWAR projection of position players while losing Kyle Tucker. It's hard to say the Cubs are not interested in sustainability when they're clearly sustaining their production based on fWAR projection systems. As teams add players, they will drop in fWAR projections, but their current projections put them as a top-10 team almost any year without adding anything and there is a bulk of the offseason to go. The Cubs reportedly have at least $40m left to spend, and they can't and won't spend it on 15 Tyler Austins.
Beyond that, the Cubs' position players especially, have been with the team for a while. Hoerner and Happ were drafted by the organization and signed a second contract, Seiya Suzuki is entering year-5. Pete Crow-Armstrong, Matt Shaw, Miguel Amya, Michael Busch, Owen Caissie and Moises Ballesteros are all controlled for 4+ years. Dansby Swanson is three years into a seven year contract. The Cubs are sustainable.
Would it be nice to see the Cubs add some impact talent? Sure thing. I think that's going to happen. I don't agree with you on Imai and the Giants, there's almost no smoke out there on it. The smoke has been billowing towards two teams all week, the Cubs and the Yankees and recent reports from the Yankees owned sports network tonight suggest the Yankees don't feel confident he'll end up there. Could the Giants play possum? Sure, let's not count it out, but beyond personal opinions, there's nothing suggesting the Giants are that into him here. In fact, Ken Rosenthal just a few days ago said that the team didn't seem prepared to sign at the top-of-the-market and Imai, at this point, probably is the top-of the market (or second behind Valdez).
So let's see where it goes. Ultimately, none of this is really why the reasons behind what I was showcasing before on free agents aged 25-30; the Cubs are not looking for big spending when they fill out a bench. Will they break the mold this offseason and add Imai, or Bregman, or something like that? We'll see. As of now, I think the winds on Tatsuya Imai are blowing towards Chicago based on all publicly held information. So while I wouldn't buy an Imai jersey if I were you, I think getting a little hopeful there feels realistic.