Premier League chief executive Richard Scudamore insists that promotion and relegation are not up for discussion.
Scudamore addressed a Global Sports Summit in London and took the stage with Roger Goodell, commissioner of the NFL, whose format does not feature relegation.
"Relegation is the best thing that happens in our league and the worst thing that happens. It keeps the season alive and keeps a whole lot of interest. If a team is in danger of relegation they are living in fear.
"It is the fundamental difference why we can't copy you (the NFL) and you can't copy us.
"Our league is a ladder to the leagues below and an escalator to European competition above.
"The whole raison d'etre of the way the league was set up is to build a ladder."
Goodell revealed the NFL had been looking on the format of relegation with interest but added it would not fit their structure.
Scudamore argued that the success newly-promoted Hull have enjoyed keeps interest levels high at home and abroad.
"If you look at the league the quality of football is fantastic and you have some unbelievable stories," he said.
"Hull City are in the Champions League places. The world had not heard of Hull City until the last few weeks. The world had heard of Tottenham Hotspur and they are languishing at the bottom of the league.
"You have the Manchester City story, whatever that is, the Newcastle story, whatever that is, and I have not even mentioned the four teams you might expect me to mention in Manchester United, Liverpool, Arsenal and Chelsea.
"Ultimately, you have to keep interest going. That is the most important thing."