“They couldn’t afford him,” Robertson said. “It wasn’t in his interests to race for what they were offering so he’s going to go rallying instead.”
Robertson said he believed McLaren had already signed Jenson Button.
Raikkonen is trying to find a drive in the world rally championship, Roberston said, although nothing had yet been sorted out.
He made his world rally debut on his home Rally Finland last August, setting competitive times before crashing out.
“He wants to be back in F1 in 2011 but with all the money he has earned he doesn’t want to go in a medium-type team for money,” Robertson added.
“The same criteria would apply as this year – he’d only go where he feels he has a chance of the world championship.”
Asked whether Button’s appearance on the market had wrecked Raikkonen’s hopes at McLaren, Roberston said: “If they hadn’t gone for Jenson, they’d have gone for someone else.”
Raikkonen, who won the world title for Ferrari in 2007, was forced out of Ferrari at the end of this season to make way for Fernando Alonso, despite already having a year left on his contract.
Raikkonen is being paid a sum believed to be in the region of 20m euros not to race for Ferrari in 2010, but still wanted to be paid what he felt was a fair sum to drive for another team.
Robertson would not confirm the Ferrari payment, describing the arrangements with Ferrari as “confidential”.
I would put him in the top 20 of the greatest drivers of all time, you will be missed
Although he won the Belgian Grand Prix, Raikkonen’s final season with Ferrari was a disappointment, with car that was never the fastest in the field.
He said: “Kimi wanted a winning car, only McLaren could supply that and he only had them in his sights. He didn’t want another year like this one.
“But they had their issues with Mercedes, Santander and the FIA and from a financial point of view they are not the powerhouse they were. They couldn’t afford him.”
Mercedes announced on Tuesday that they were selling back their 40% shareholding in McLaren and buying the Brawn team instead.
Spanish bank Santander will sponsor Ferrari next year, although they will still retain a smaller presence with McLaren.
And governing body the FIA in 2007 fined McLaren $100m (then £49m) after they were found guilty of possessing confidential Ferrari technical information.
Asked how Raikkonen felt about the temporary end of an F1 career that started in 2001 and in which he won 18 grands prix, Robertson said: “He’s one of those guys who moves on quickly – he just said ‘now we concentrate on rallying’.
A McLaren spokesman refused to comment on Robertson’s remarks.