Fergus Linehan called on the Scottish Government and the city council to take a more long-term view of the event after years of either standstill funding or slight cuts.
Linehan, who is overseeing his final event, said the festival needed greater protection from “bumps in the road” which might hit its finances.
He suggested the festival should be looked upon as a key historic asset for the country in the same way as Edinburgh Castle.
Mr Linehan was speaking weeks after a new 2030 vision for Edinburgh’s festivals warned they needed new investment models to give them “maximum resilience” in future.
The blueprint was published by Festivals Edinburgh, the umbrella organisation that has brought together senior figures in the city’s major events since 2007, and the Edinburgh Festivals Forum, which the council, the Scottish Government, events and tourism bodies and Edinburgh University sit on.
It stated: “The Covid-19 crisis brought into stark relief the fragilities of the entire culture sector, especially its long-term financial sustainability and ability to invest in change.
"Pre-pandemic, the sector had already seen a difficult decade since the 2008 global financial crisis with the festivals seeing a 30 per cent real terms reduction in public grants which they had balanced by diversifying their income streams.”
Mr Linehan said: “Looking back with the benefit of hindsight, we probably think about these things in too short a timeframe.
"The question isn’t really about a cost of living crisis, terrible inflation and times being tight.
"The real challenge is what the long-term perspective is. The danger you hit a bad time, the investment drops down a bit and that then becomes the high water mark.
"I think there needs to be a long-term view and an acceptance than in any given year there may be some bumps in the road.
“We are in the 75th anniversary year now. Taking a 20 or 25 year view of the festival sounds very grand but it would take the politics and immediacy out of it and at least set a goal of where things needs to be.
"I also think that festival needs to be financed in a way that isn’t based on cashflow for that year. It should be treated more like an historic asset like Edinburgh Castle."
Under its current funding deals, the EIF gets more than £5 million a year from the Scottish Government, the city council and Creative Scotland, and is the highest subsidised event in the country.
Linehan has previously been critical of the city council in particular for regularly targeting the EIF for cuts.
Speaking in 2019, he said: “I just want to know what the plan is. Do you just keep cutting or is there a point at which the festival ends? In three years time will all roads just lead to a swamp? Is the only strategy to keep on salami slicing? If that is the case then the festival will end.
“If we’d been bouncing along at the same level for the last decade and we had to take our medicine that would be different. But you can’t deteriorate a core funding base indefinitely.”