I mentioned the phrase "the art of DJing" in another post. When I worked (in Top 40) my mic was open between almost every song, twice if I had a spot break between songs. I liked to work on the "flow" of the music I played, given the playlist restrictions and all. While a song was playing I would "get a vibe" from a song that I would pick to play next. I couldn't get that "vibe' two hours in advance picking out my whole show ahead of time. While listening to a song a clever way to tie in a lyric with the next live promo would come to me. That couldn't happen two hours ahead of time. I was a "live" DJ. If I VTed a show now and then did one live it would sound like two different people.
Brilliant observation. In one of my former lives I did DJs gigs both as a paid employee and as a volunteer, on a variety of stations, commercial, college FM and carrier-current. I understand that "vibe" and knew a good inspiration didn't come during the prep time or its modern equivalent on so many stations, the voice-tracking.
I think this also contributes to what I think is the losing of a fine art. I can listen to, say, Terry Lee's Internet show much as I could his old shows on Pittsburgh, McKeesport and Mon Valley stations. I can appreciate a Frankie Day, though I admit I can't listen to him for very long and in morning drive I'm flipping the dial frequently for news and talk. (I only use these two for examples, my point is upcoming:)
My point is, I don't listen much to radio for the deejays, and I think it largely is because the voice trackers aren't more than a cracked mic that is inserted to give the listener the impression that there is more than a jukebox on the other end of the transmitter. I preset a bunch of stations in two states for music. I don't believe I preset any of them for personalities, because I don't think there are any. And your point explains it.