
^^^In 1989 when TFF came out there was only TNG, TOS and the TOS movies, no so many incarnations.
TOS, TAS, TMP, ST II/III, and ST IV all had very unique main themes. It was only TNG that borrowed TMP's, when the original theme by Dennis McCathy was rejected. Then Goldsmith decided he wanted to use it again for ST V.
And why not. Had Horner returned, he would have re-used his own themes from TWOK and TSFS, too.