This could indeed be true of 5-stringers but I'm an old-timer 4-stringer funk player where four is enough for me. So having thinner strings thins out the sound even if boosting left and right.
In all seriousness, I learned this on four strings. And I may be as old time a funk player as you.
In the late 70's/very early 80's, before decent fives were easy to find, I detuned fours to BEAD. The last was an aluminum necked headless Kramer Duke I got in 1981. I did not use super thick strings, my "B's" were typically around .110. I learned alot about string control with those basses and it's stuck with me all of these years. And to this day I hear fives with .130+ B strings that don't sound as deep and full as my .120 - .125 strung basses.
I know that might seem counterintuitive, which is probably why more folks don't do it/attempt it.