Quick answer: Players don't know they can file bug reports. A 'Help' menu link to bug reporting raises awareness; report count grows.
Visibility of the reporting feature drives reporting volume. Make the path obvious.
Help menu link
'Report a Bug' button in main Help menu. Discoverable.
Onboarding mention
First-launch tutorial mentions the feature. Players know it exists.
In-game shortcut visible
F2 keybind shown in keybind menu. Players who explore find it.
Pause menu surfaces
Pause menu has the option. Friction-free access.
“Bug reporting is a feature. Treat it like one; market it like one.”
If your game has bug reporting but players don't use it, the marketing is the gap. Surface deliberately.