Honestly I don't see much connecting "70s-ness" thread between these. You can kind of take a guess at the era by the color tones, or for those movies with a contemporary setting, the style of clothing and cars. But otherwise there is huge range in old movies.

I've got this theory that although technology advances and social mores change with different social standards being imposed on art (e.g. Hayes Code), artistic merit is more or less evenly distributed through time. That is to say, old things are about as likely to be meritorious as new things, there's no general trend of newer = better. However the general public realizing this would be bad for business, new productions don't want to compete with the best of old generations, and so there are efforts to persuade people that old content is unwatchable and a waste of time to even consider. People are strongly encouraged to favor new content over old, for instance by having an averse "eww icky" reaction to black and white movies or even technicolor. Technical developments in film stock, SFX, etc are touted as being extremely meritorious and are heavily emphasized in the promotion of new movies because this is the competitive edge for modern productions.

I think Stanley Kubrick's films alone are more different to one another than half the Hollywood films made today.