I hike alone frequently and where I go in winter is quite limited in terms of fire-sustaining materials. I could build a grassfire but it would be on its way quickly.
I think in terms of injury and needing to survive without full mobility or body function. Such injuries might preclude travelling far enough to get wood for a fire or being able to construct much of a shelter.
So my gear set for hiking has materials so I can insulate myself and roll up into a large poncho while setting out my rescue beacon and hunter orange materials.
I still have fire starting stuff (3 ways) because it's good to have options and it doesn't weight much. But the injury-while-solo scenario for me suggests fire starting isn't necessarily the primary thing to concentrate on.
"It Depends."