This is sadly very true...i played in a wedding band for a few years and the ahem, "soundguy" was the singers brother in law who knew nothing about sound, but he had a decent setup(not that this matters in the hands of the unskilled), he also setup all the PA, so it was a win for the singer...
Anyways, the bass always sounded like hip hop bass on EVERYTHING, oldies, 70-90's variety music, no definition or midrange, just sub lows and he always insisted on pre-eq XLR, he'd give me the whole line about "bass should be felt, not heard"....
Anyways, if I didn't have decent stage volume I couldn't play well because of his mix, I ended up quitting when the pay never went up.....
Now i wouldnt put up with that crap!! I also worked with great soundguys willing to work with ya so its hit or miss, get a good preamp/DI pedal to run after FX, I use the B7K nowadays but plenty of other good ones now as well, that ampeg DI looks pretty cool...