Most are oblivious to what benefits RUN brings to the party.
This is the big reason. People are still stuck thinking RUN = TANK1110101 without understanding what exactly a "tank" is and why it's totally useless in FFXI. RUN is a support DD, they deal damage while being impervious to high damage magic attacks and conferring much of that immunity to their party members. Valiance and OFA are godlike in their utility.