Tottenham remain in the hunt for the Premier League title ahead of Sunday's North London derby against Arsenal, while they are set for another Champions League campaign in 2017-18.
However, Wenger believes it will be difficult for Tottenham to maintain their challenge over the years due to the club's wage structure, with the likes of Harry Kane and Dele Alli able to earn more money elsewhere.
"For a longer time, if the budget is too much different, it's impossible," he said.
"When you get to a level, at some stage the best players want to be paid like the other players at that level.
"If the differential is too big, you're never able to keep your best players."
Tottenham – second behind leaders Chelsea – are set to finish above Arsenal for the first time since Wenger took charge in 1996.
Spurs are four points adrift of Chelsea and 14 clear of Arsenal.