"The Lions are probably the most powerful brand in world rugby," said Fitzpatrick, who led his country to a series victory over the Lions back in 1993.
"You ask anyone who has played against the Lions and they'll tell you they're one of the greatest teams to play against.
"Winning that third Test against South Africa was paramount but even had they lost they'd still be a viable brand."
And Fitzpatrick, whose media work ensured he was a keen spectator during the 10-match tour of the Republic, believes more must be done to expand the Lions concept.
The ex-Auckland star has dismissed talk of the Lions being irrelevant in modern-day professional rugby, claiming instead that Britain and Ireland's elite should be given more time to prepare ahead of future tours.
"Without question they have a future," added Fitzpatrick.
"They say they need more (games), so give them more matches to make them more competitive.
"But look at that series just gone - they should have won it and could have won it 3-0.
"Even if you just look at them in terms of being a money-making brand, they're phenomenal."