Agree, and here's my experience; I have a five string set-neck bass that has a two way truss rod. The "head" of the truss rod is a 1/4" nut welded in place on a threaded main rod. The weld broke and the nut would turn on the threads. For a while I thought I no longer had any truss rod function. I eventually found some thread locker that would hold, and I have full truss rod function again.
During the time I thought I had no truss rod function, I bought a set o D'Addario Prosteel extra-super light strings, gauges, .035, .055, .075, .095, .0125. My usual strings for this bass were Prosteel custom light .045, .065, .085, .105, .135.
The extra super lights played great and sounded clean / clear, but they lacked punch, and had significantly less volume than the strings I usually played on the bass. The .035 "G" string was super thin and weak sounding to the point it was unacceptable to me. I bought a single .040" string just to try to get even output for the string volume.
The extra-super light strings should have had more fundamental content, but that sure didn't translate to a tone I liked as compared to the same string in a heavier gauge, so, for me, more fundamental content did not equal thicker / fatter tone. It was very much the opposite.