Conte has been repeatedly linked with a move back to Italy since arriving at Stamford Bridge last summer, despite steering Chelsea to the Premier League title with a record-breaking 30 wins during his debut season at the helm.
Even signing a new two-year deal with the Blues has failed to quell reports that the 48-year-old is eager to return to his home country, but Ranieri acknowledged that Conte may have a tougher fight in front of him this season.
"The Premier League remains the best and I have not been convinced of Conte's desire to return home," he told Gazzetta dello Sport.
"Maybe he was expecting a different transfer window but for a few years, [Roman] Abramovich has not paid crazy prices.
"Manchester City and Manchester United on the other hand have made big buys so I can imagine that for Antonio to fight on more fronts with the same players is more tiring."
Chelsea currently sit fourth in the Premier League table, already six points adrift of leaders Manchester City and Manchester United.