Basically for the Cubs in the upcoming 3-4 years, our young nucleus will hopefully be Castro, B. Jackson, Soto, Garza, Cashner, McNutt, and Marmol, with hopefully Barney and Colvin being good role players and possibly a guy like LeMahieu or Flaherty becoming another average major league regular. That's not bad, but it's still going to require very good decision making by Hendry or a new GM to bring in outside talent to surround them. At least at this point, that's not a nucleus that's going to do it by itself. If Hendry keeps making mediocre/bad decisions on long term contracts, the young talent isn't going to be good enough to make this a consistent winner.
You're seeing a lot of it play out this year. We may have Castro, Barney, Garza, Marmol, and Soto already on the roster, but when you surround those guys with mostly garbage, it's not going to be a very good team. I'm not sure getting a "wave" of B. Jackson, a healthy Cashner, and McNutt exactly elevates the talent level to a 95-100 win team.