But there are countless resources to find proper anatomy, books, the internet, nude models, posing software...
Proper anatomy doesn't always go hand in hand with anime physics and anatomy most of the times. It helps give you the basics but in the end you can't expect anything realistic.
If we have to bring up actual human anatomy and such, we won't be able to correct our greatest flaw; the nose. As well as numerous other parts.
However, the body is one area which, while certain creative license can be taken, it's simply weird when a vital selling point such as the breast is misplaced. The anime face is a stylistic choice that we've all gotten used to through cartoons and similar media, but almost every creator who doesn't work with deformed bodies (Chibi and the like) chooses to work with an anatomically correct, if malnourished, female body.
Some, like Hyung Tae Moon and his long legs, might lengthen different parts of the body beyond the norm, but they're all properly placed, while the most eye-catching visual, the breasts, are often under intense scrutiny. You already get lots of complaints about over-sizing breasts, or balloon/melon breasts, and attaching the breasts to the collarbone is another thing that just looks off.
If someone decided decided, fuck it, let's start putting the legs just under the rib cage, that would look very weird, or if someone placed the head too low on the neck such that the person looks like they have little neck at all, or too high such that it becomes a giraffe neck. When things are placed wrong, people notice, because it's unnatural. Things that are designed to be unrealistic from the start (Anime heads, western cartoons, etc) don't have those same problems, because we go into it understanding that, but when you pursue a relatively anatomically correct proportion, you want to also be putting the body parts in the right places.