I believe to this date the cast of Friends were among the highest paid actors in the history of television and they are still getting paid from the show. Schwimmer's father was an entertainment lawyer I believe. The story goes he convinced the actors on the show if they have individual lawyers and individual agents that any of them could be cut from the show. He said you have the number one show on tv. Have a united front. It's all of you or none of you. He negotiated toward the end they would make one million an episode each plus residuals making them the rich.
Now you have guys like Ray Romano who starred, wrote and owned the syndication for his show who made sick money and Seinfeld who might be worth more than 300 million have surpassed this.