This is something the bears couldn’t/wouldn’t do. The bottom line however is that all the best teams run for average and/or high yards per game.
I think it was more about 'couldn't' than 'wouldn't'. For most of the year the OL sucked. Tackles lost most of the time and the interior featured a broken/recently retired Kyle Long and two other players whom just couldn't get chemistry going.
The side fans don't see is Nagy probably had a good idea what they were bad going into the season. He probably saw them get their asses kicked by Hicks & Co in practice, identified their limitations and tried to play call away from areas of weakness.
To the fan it looks like he won't try things that seem fairly straight forward. The truth is Nagy just doesn't believe his players will be able to execute.
There's the opposite side where coaches over trust players to overcome weaknesses. The best example of this is when
Osi Umenyiora beat Winston Justice for 6 sacks in a single game. I've mentioned this before, but Andy Reid believes in his players to a fault. He strongly believed that the his second round, second year player, was ready to handle his blocking assignments. The announcers were openly wondering why Reid didn't give him some help against Osi.
I guess the lesson learned is that coaches know these players abilities way more than any of us. That's only part of the picture. From there the team can still fail in giving the players too much or not enough to do. It's a delicate balance, which is often hard to get right.
Let's compare that to our jobs. Often our employer either gives us too little or too much responsibility. Same thing happens in the NFL. The only difference is when the employee or manager (coach) fail it's on a national stage.