I testify, the money was good!Seinfeld. End of story.
Name me another show with its longevity that was as consistently well written? I don't think you'll find one. The amount of money that show has made and the amount they were getting paid, which even by todays figures were massive, is a testament to its success. They sold advertising on it for over 1mill a minute, that's second only to the superbowl.
Personal opinion of course.
Edit: Wilfred, are you kidding me? We are talking about the best show of all time....