TL;DR: Supplements are mostly a waste
I don't think this is a useful statement.
Instead I would say that the need for supplements is strongly individual.
You're young, live in the tropics, and work outside all day? Nah, you probably don't need vitamin D supplements. You're old, live beyond the Arctic circle and it's now winter? Yes, taking vitamin D supplements is probably a good idea for you.
Take a blood test and look. Do you need potassium? Maybe, maybe not. Do you need magnesium? Maybe, maybe not. Do you have glucose issues? What do you hormones look like? How's your thyroid?
Everyone is different. There is no good generic advice with regard to supplements. Look, test, figure out what your unique body needs now.
I think we have a different mental model of the sort of person who clicks on the link and investigates examine.com. My impression is that the average person with no particular health problems wants to know which supplements have the largest effect sizes, which doesn't exist all on one page on examine.com unfortunately.
Examine.com's Guide to Supplements.