So mr. floaded, are you saying that there is a difference between changing the key center and modulating?
kinda.
Check out the song "Calling my name" by Hezekiah Walker. The verse has a key center change from Eb to Ab to C#. The key center moves because of the type of chords being played. But anyone not really into music or music theory (musicians and skilled singers) probably wouldnt notice, but think it rather weird movements. but the key center changes but it fits with the basic structure of the song, meaning it doesnt feel like you've moved the whole song anywhere.
Then the bridge is in the key of Bb (or F# cant remember now sitting at my nonmusical computer at work. lol). explicit key change. but its an entirely new section of the song.
Quite different than repeatedly taking the entire song or a repeating vamp up a half-step or a whole-step. The feeling is that whole song has moved/changed (im assuming this is the exact intended effect). Even if you go back to the top, you have to do it in the new key, or EXPLICITLY walk it back down (which i've heard some songs do). Not that its a bad thing, but i just havent heard other styles do this.
Is it taboo, or just not necessary? I dont know. But i would definitely imagine that such key changes could turn out to be a engineers nightmare for a studio produced album!