Linus makes certain deductions about his new partners in crime. Rusty, he thinks, comes from a poor background--not because he's a thief, because Linus knows better that to assume everyone steals because they didn't have money. He himself steals because it's the family business. Certain people (Danny Ocean in particular) do it for the challenge. Certain people do it for the thrill. The thing that makes Linus think that Rusty, regardless of his reasons for getting into the business, was once poor is that he eats constantly. He makes Linus of the phrase, "living hand to mouth."
The way Linus reads Rusty and Danny's relationship is that Rusty was the poor friend, poor cousin, poor something, and Danny was more comfortable but he wanted to help him, got into trouble with him, came up with schemes to get them both wildly rich as fast as possible. Rusty, Linus thinks, resents Danny for this somewhat. He expresses it as weird jealousy over Danny's obsession with his ex-wife, but Linus is pretty sure that's not what it is, really. And if it's not about the woman, it's almost certainly about the money. So Linus sees that Rusty is comfortable now, but thinks that he wasn't always, and deduces that he still perceives an inequality between himself and Danny, no matter that they're friends.
The thing Linus forgets is that he's dealing with consummate con men. Or, he doesn't forget, but he doesn't realize that they're playing with him, seeing what they can make him believe for the challenge and the thrill of it, stringing him along. Rusty's reaction to Danny's ex-wife reads wrong to Linus not because it's not the cause of their conflict, but because there's no real conflict at all. Behind the scenes, they're slapping each other on the backs for a drama well-played for their audience of one, and that camaraderie doesn't entirely disappear, even when they're on stage.
After the heist is over and Linus is finally privy to this joke played on him, he reevaluates what he's seen between them. Rusty, he thinks, grew up poor, and learned to be practical, waste not, want not, made himself into a good organizer, to make everything run smooth. Danny, he thinks, grew up with just enough money to fritter away, lived beyond his means, charming and debonair. Danny can think of a thousand and one ideas to get himself out of the hole that he's in, but somehow he just digs himself deeper--three to six months in prison over the Vegas job being case and point.
There is an inequality between Rusty and Danny, it just doesn't lean the way Linus thought it did. Rusty, Linus thinks, takes care of Danny, because Danny is utterly incapable of taking care of himself.