Your perception is born out of your own frustration. Yes, model photoshoots get the tweak. No, they do not get the tweaks you think. Particularly the solo models. I pore over each new photo and regularly find blemishes that logically would be "edited out" according to your expectations. Instead, they merely get covered up with makeup depending on the goal of the cosplay.
The notion that because you can occasionally perceive a "straight line" on her ass depending on the angle is absurd to the point that you would have to have driven yourself insane with discontent, lust, and shame over that lust. Humans have this bit of bone called the pelvis. It sticks out at points and often leaves a concave shape for MOST body types. If one is a bit more physically active, this upgrades to a pseudo-straight line. This is of course from a set of different angles and poses. One's silhouette is dictated by a variety of factors: musculature, body fat distribution, pose, garments. There can also be the matter of skin elasticity.
I really don't expect decent analytical skills out of a forum that repeatedly posts fully clothed and modest women as if it's porn, but damn is it hard to get you to absorb basic knowledge like this. You'll never be fulfilled with the mixed-up standards I've been seeing.
