The issue is that the NHL is in a salary cap era, it makes it very hard for teams to be a "contender" for more than 1-2 seasons. Chicago had its run between 2010-2016, when their players were not only young but also cost controlled, basically they could afford to pay their top players, but their secondary ones as well. Once their core was locked in (Towes, Kane, Keith, Seabrooke, Hossa, Crawford), it became very hard to afford good secondary players to help insulate their core, ever since 2015, they have had to rely on young and cheap options.
The best way I can put this, imagaine building a home- You spent the excessive money on the foundation, but then you had to use what little money you had left to not only build but substain the rest of the home. Due to lack of money, the home detriorated and as a result it crumbled to the ground, leaving nothing but debris and ashes, the home is gone. That's essentially what happened to the hawks here!