What was it with those studies about many vegetables containing less of various nutrients than they used to and how often that related to their size, look, amou

What was it with those studies about many vegetables containing less of various nutrients than they used to and how often that related to their size, look, amount of inputs needed, resistance to various ailments and removal of various inconveniences, etc Can we assume incentives are aligned properly to avoid more such effects? I'd assume the opposite.