Judging by what I see on Instagram those who are doing baking without a mix are going in the opposite direction of ATK - super simplicity. I was a huge fan of Cook's Illustrated when it first came out and while I learned from them everything was always many steps, very fussy, and not really approachable for this newbie. I still have the first two or three Cook's annuals.
But then they became a thing. And started selling the same recipes six different ways. And while they still "don't accept advertising" they recommend products based on testing but also have click-through to Amazon where they make money if I buy something.
I always feel bad for people who lose their jobs in a big layoff but the world changed and they did not.