The Bears gave up 3 good picks to move up ONE SPOT for Trubisky. They gave up the equivalent of 3-4 more high picks to get Mack. They have up a 4th rounder next year to move up 14 spots for Montgomery. They have only 6 picks next year (Round 2, 5, 6, 6, 7) and only one in the top 150 picks or so. So they have no salary cap space and no picks to trade for next year.
The Trubisky trade may end up being the worse trade in NFL history given what they gave up to move up 1 spot to #2 to draft a Trubisky in a draft where two potential Hall of Fame QBs were drafted at #10 and #12.
2017 draft-pick No. 2: Mitch Trubisky, QB, North Carolina
Bears traded
2017-3: 49ers — Solomon Thomas, DE, Stanford
2017-67: Saints — Alvin Kamara, RB, Tennessee (via 49ers)
2017-111: Seahawks — Tedric Thompson, S, Colorado (via 49ers)
2018-70: 49ers — Fred Warner, LB, BYU