Spurs boss Antonio Conte says no manager in the world would be able to quickly fix the problems at the north London club.
Conte was appointed in November and inherited an inconsistent squad.
The trend has continued under the 52-year-old Italian, with a win over Manchester City followed three games later by a loss to Middlesbrough in the FA Cup.
"Tottenham's story is this, many ups and downs," Conte said.
Speaking before Tottenham's Premier League match against Everton on Monday, he added: "To be competitive and try to win something and try to fight for something important and to become a strong team, the first thing that has to happen is to be stable and to avoid these ups and downs.
"To do this and to change this type of situation that has been for many, many years is not simple. In the short term it is impossible to do this, not only me but for every manager to come here.
"This is the story of this club for the last 20 years."
Tottenham, who are currently seventh in the Premier League, have Lucas Moura and Rodrigo Bentancur available for the visit of Everton.
"Bentancur is available, the same for Lucas Moura," Conte added. "For [Oliver] Skipp and [Japhet] Tanganga they are not available, we have to wait."
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