> but rarely is a change in UI/UX objectively bad
We're not looking at a box with unknown contents that we would need to go by probabilities. We can just look at the thing.
> The article you've linked has been fairly criticized for it essentially removing controls from their methodology by things like using lower contrast buttons for the 'flatter' designs, which is not essential to the design paradigm.
I can, right now in Win 10, show you plenty examples where there is no contrast and no distinction between an overlay window and what's behind it. Not low contrast, exactly the same color.
> Ultimately, I'm still going to argue that this is a matter of subjectivity and as we age the less accepting we are to change
This is the same indirect reasoning as "people like what they used first", which in my case is provably, objectively, false.
I might as well say "as people age and grow in confidence and experience, they trust their own judgement more, and care less about just going along with whatever is pushed just to fit in" or anything like that.