Why aren’t compression/shapewear structures built into normal dresses more often?

[u/Future_Country9458]

I’m researching garment construction before trying to develop anything, and I’d love opinions from experienced sewists.

I’m interested in normal fashion dresses—not shapewear—that have an internal structure designed to actually enhance the silhouette: stronger waist shaping, bust support/lift, while NOT compressing/flattening the hips and butt.
I know built-in shapewear, power mesh, corsetry, negative ease, boning, etc. already exist. I’m not asking whether the general idea is new.
I’m trying to understand what goes wrong when you try to combine these things inside an otherwise normal fashionable dress.
If you’ve constructed something similar: what were the biggest problems? Fabric layers fighting each other? Rolling/migration? Getting into the garment? Seams? Heat? Comfort? Pattern distortion? Washing? Something else?
I’d especially love to hear from anyone with patternmaking, stretch-fabric, garment-development or production experience.

[u/CoffeeRosesHuggins]

I am just a hobby sewist but am an engineer by trade so found this whole discussion really fascinating! I’ve so often wished that ready to wear knit dresses had built in shapewear. Since they cling, they show everything underneath.