People prioritise different things OP, that's all. Some people have low self confidence too I think and maybe don't see the point in making an effort as they feel the end result will be unappealing whatever they do.
I don't think I'm especially appearance focused, yet I do wash and blow dry/straighten my hair daily, have it done (dyed and cut) every couple months, shave, I wear a full face of makeup every day (primer, foundation, blush, brows, shadow, liner, mascara, highlight, ranging from subtle to heavy) which I love and find super creative and enjoyable. And I only wear clothes I feel fit and look nice/stylish, though I only buy cheap. Always topped off with a perfume and jewellery.
But for the people I know that's just normal and par for the course. The amount of makeup differs but it would be unheard of to leave the house without being clean and hair done, face made up and nice clothes.
I don't honestly even notice/register when people don't 'make an effort' with their appearance as I don't care. Although there must be social conditioning going on, I don't feel that I do all of this for others or to look good for other people, I feel as if I do it for me. Because I enjoy looking my best, I find makeup and clothes fun and creative, and why wouldn't I want to look the best version of myself I can possibly be?
Maybe as life progresses my priorities will change, but maybe not. To an extent I think it can be passed down through social learning. My mother would never leave the house without mascara, foundation and lipstick and freshly washed hair and i've wound up the same.