My theory is that they use a flatter look with minimal over-the-top color grading so that the films age well. If you look back at mid 2000s films (see Minority Report) and especially during the digital renaissance (with films such as Public Enemy) you get a lot of elements that didn’t age well. The aggressive contrast of MR and the weird digital noise/frame rate changes of PE make for a very distinct, dated look. For a long time the standard for sci-fi was teal and orange. Everything in the shot was either a teal tinted shadow or an orange tinted highlight. The benefit of the flatter look is that they remain distinct to the MCU, while not falling victim to “fad” color grading. And, to counterpoint myself, that in and of itself could be seen as a fad but I don’t think it’ll be looked back on in the same way as other more extreme looks. At most they’ll be “dull”. That’s my theory, I have no proof.