Mr. Burns, Principal Skinner, and Ned Flanders Have Been Fired From The Simpsons!
Harry Shearer, who is also Derek Smalls in Spinal Tap, was holding out for more money, and wanted all the voice actors to get more out of Fox for all their work, including merchandise. The others signed their contracts, but Harry was holding out, to be free to work on other projects, and maybe get a bit more money.
Are they going to recast these characters? Are they still talking? Will the characters just disappear from the show after 26 years?
We can only wait and see.
Are the actors hurting for money, earning $400,000 per episode? No.
Is Fox being greedy as f***, not giving them any chance for profit sharing? Yeah, pretty much.