Nobody will have a reliable answer because nobody knows. This "attackers won't shoot" issue has been on the forum for many months, at least; you can search to find more discussion.

Some players seem to shoot more than others (not that either player type necessarily scores goals), so it might be a hidden player characteristic.
You can try arrows, but I have had even DCs who will shoot with a down arrow.
It could be any skill, again nobody knows today -shooting, speed, aggression, strength, finishing... nobody knows how individuals skills act.
You can change your pressing or forced counter attacks, I sometimes think my players shoot father out when pressing low (I also wonder if down arrows help with the same, while an up arrow asks the player to dribble and drive forward before shooting)
Can change your passing focus and distance, long both flanks might lead to many cross attempts to the box; mixed might have players connect a number of passes before shooting.

If you are winning, and especially if your ratings are consistently over 7, you probably don't have a real problem. If you have players rating 6-7, never over, I'd sell them.