DG, one of my favorite quotes about statistics: "Torture the data enough and it will confess to anything." <smile>
Actually, in all too many cases, you are right. Composers either tend to write for bass (Beethoven, etc.), or relatively ignore it (Copland, among others). Most do opt for "ignore". For film scoring, what is in AP Strings, sadly, is probably enough (growl, whine, or menacing rumble). For traditional orchestral writing, the answer would be different.
One of my favorite double-bass stories (a true one): Gary Karr (a now semi-retired double-bass solo concert artist - am guessing he is now about 70ish or so, and arguably the best solo bassist ever (Klaus Stoll and some others also rank up there), when in college, was in the university's chamber orchestra as the only bassist. At every rehearsal the conductor kept saying the usual, "The bass is too loud." Gary decided to play the entire concert keeping the bow an inch above the strings (while fingering every note, of course). Afterwards, the conductor commented to him that he had played extremely well during the concert (note: the story was told by Gary, himself).
So yes, the bass: best seen but not heard.