Hamilton's current Mercedes contract runs out at the end of next season and there have been suggestions that the six-time world champion would consider switching to Ferrari for the latter stages of his F1 career.
The British driver is just one Drivers' title away from equaling Michael Schumacher's all-time record of seven championships and Ecclestone believes he should win that with Mercedes next season and then walk away from the sport as he would be beaten at Ferrari.
"There has been change at the top and the new people are not so enthusiastic about Formula One as the old people used to be," Ecclestone said to the Daily Mail. "If I were Lewis I'd think, 'I've won another title', and I'd stop. If Charles Leclerc stays at Ferrari, I'd put money on him to win against Lewis. He's not necessarily better but he is established in the team.
"Ferrari is a strange place to work. Lewis doesn't speak Italian. They might gang up on him - or fall in love with him - but I don't think he would do as good a job for himself or the sport as he is doing with Mercedes."