Hey Charles,
First and about the introducing sequence of Contempt from JL.G. Those 3 colors are red, yellow and blue, so as you know, it could refer to the Romanian flag but certainly not to the french wich is more like blue, white, (an i'm not supremacist) and red. So why the fuck Blue Yellow and Red ? Godard is he finaly a creepy secret soviet romanian spy ? hummm... No.
These colors refers to the antic statuary and dramaturgy trichromy ( hell lotta "Y"). Godard was obsessed with antic ages, specially greeks and he made this ref' in other films like Pierrot Le Fou where he painted himself parts of set with those colors. greeks and others untill middle ages used this colors for two reasons. They were the most simple pigments to find, create and melt to do other tones. And secondly they became across the times, symbolic colors of life or at least of Dramaturgy as the representation of life. the Blue for the nostalgia or freedom, Yellow for spirit/intelligence or arrogance and red for love or hate (note that every color haves a dual pole that makes them positive or negative, depending on the point of view, and that's fucking not told in all those "how to cinematic color grade my stuff 'cause i cant color think it ?") So Godard just tought these colors would repesent the cinéma itself, like theatre successor, and subline of the movie, wich talks about movie making.

Then about Marvel's flat colorgrading, you are right to say it is not a mistake but an esthetical choice, that leads us to an un-thought erea of the debate. Esthetical and political questions are much more linked that we usually think. you here just say "hello this is just so 2000 to do deep blacks and saturated warmer tones" reposing on fashion and not analysing it.
This flat-grading fashion comes from the music clips (and others internet things) where dp's lighten their sets refering to the view of their display solution, screening raw or slog footages un-graded, like if it where standard contrasts on screen. It results by low contrasting at grading time to keep dynamic range cinematic. Politically it reflects the marvel's choices to make the films the most large audience possible. Best proofs for this are the overdominant uses of humor and specialy in dramatic scenes that results by making these often extaordinary moments looks like christmas familly walks along the seaside. You know by an untold pact that your heroes wont die, this is the message. Deep blacks and brigther colors are the clues of a darker End and some more passionated characters... (like in Batman vs superman, comparing comparable stuffs)

Thank you for reading and excuse my english, i'm a french bastard ;)

Florent