Yes, but:

• the switch to PVC insulated wire as we see in the photo coincidentally happened around the same time as the code cycle that required every box in residential to have an EGC.

• Many places were wired with an EGC long before that because of local code, especially multifamily properties. If metal conduit, AC, or MC cable was used, that often is or contains an EGC connected to the box via the box clamp.

In those cases where the box is grounded according to code of the time it was put in; it would be irresponsible to advise people to "just wire it as is without a ground wire", as the mechanical mounting of the fixture to the box may not be sufficient to ground the exposed metal parts of a fixture, whereas the ground wire provided always is unless something broke.

And it hurts nothing to put a 15¢ ground-screw or ground-clip in even if the steel box is not grounded.