The passing of our friend Joe Alaskey led to a number of news stories that were a little confused or confusing. Joe was a voice of Bugs Bunny, Daffy Duck, Tweety, Sylvester, Marvin the Martian, etc. At times, he was probably the most frequent voice of certain characters but he was not the only voice of any of the characters originally done by Mel Blanc. Since Mel left us, at least twenty different actors have spoken for all those animated superstars.
Why not one guy? Or at least, one guy for each character? There are two reasons, one being that if no one has a lock on any one role, it makes it harder for that one person to demand a whole lot o' money for any particular gig. Mel did that the last decade or two of his career. They weren't paying him residuals for the eleven-millionth rerun of What's Opera, Doc? so when they needed him to speak for Bugs in a new Kool-Aid commercial, he adjusted his fees upwards…and good for him.
They paid him well because he was Mel Blanc and it seemed so wrong — and possibly injurious to the properties — to get somebody else. It doesn't feel equally wrong to cast one guy who wasn't Mel to speak for Bugs instead of a different guy who also isn't Mel. So money is one reason.
Also, there is no one person at Warner's who makes all the decisions on this kind of thing. One person producing a cartoon may think Jeff Bergman does the best Bugs. Another one who's in charge of a Bugs Bunny videogame may think Billy West does a better Bugs while down the hall, someone supervising a commercial with Bugs in it may favor someone else. My late friend Greg Burson, who did Bugs an awful lot before he left us, used to complain incessantly about how he had to constantly audition for the same parts: "I did eighteen jobs for them as Bugs last month but I still have to go in today and read for the job for a different boss."
Joe endured a lot of that. He seems to have done Daffy more than anyone else but for example, in Space Jam, it was Dee Bradley Baker. (As you may have noticed, some of the folks making the casting decisions have very different ideas of what some of these characters should sound like. On one of my panels, Joe once demonstrated a couple of variations in Daffy's voice. Some directors, he explained, wanted the duck to have the voice Mel gave in the 1940's, whereas some wanted the way Mel did him in the sixties.)
I don't think this is a great way to handle this and when I've discussed it with actors or those who do the hiring, none of them seem to, either. But that's how they do it. Disney tends to have one official voice for their characters at a time but at Warner's, it's always a jump ball.