The Italian team have failed to win a race so far in a season they started with expectations of challenging Mercedes for the world championship.
"We failed the targets. I don't think there's a doubt in my mind," Marchionne said on a visit to the Italian GP.
"It's no use putting sweeteners on the stuff. The car isn't there and I don't think we developed it."
Marchionne has conducted a major internal organisation of Ferrari in recent months, and the team parted company with their highly regarded technical director James Allison in July.
"I feel quite comfortable that this team are capable of turning the fate of the 'scuderia' around. Unfortunately we don't have a lot of season left," Marchionne said
"Let them finish the season, I think we'll do the best we can for the rest of '16 and the fight starts in 2017 with the first race."
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Ferrari have "failed" to meet their expectations in Formula 1 this year, president Sergio Marchionne has said.