Most of the world walks with the left foot falling on the left side of the body and the right foot falling on the right side. I was watching some models walk on that stage thingy and notice that they mostly walk with their feet falling on the midline of their body. A large number of them actually walked totally unnaturally with their left foot falling on the right side and their right foot falling on their left side, such that their legs had to continually move across their bodies. Do they walk like that in “real life” or is it just when they are working. (For what its worth…I think it looks ridiculous.)
I don’t know, but it sure looks grotesque.
They only walk that that on the runway. It gives the hips a different (special) sway.
Pretty sure it’s just a runway walk in order to show off their assets better. I do know a female model, and she most certainly does not walk like that. 
They’re exaggerating the feminine way of walking. Men and women walk differently, due to different pelvis shapes - men walk with their feet moving in two parallel lines about shoulder-width apart, while women tend to place their feet to either side of the midline, right foot just to the right of it and left foot just to the left. Models, when modeling, frequently walk placing their feet on the opposite side of the midline, so that their right foot gets placed where the left side of their body was and vice versa. It makes their hips roll even more than average women’s do, but it’s certainly not a comfortable, efficient way of walking, and whatever footage I’ve seen of models walking around not on the runway has them walking like a reasonably normal person.
Nope. You don’t have to walk that way very long before it really starts to be uncomfortable on the hips - it’s just for show.
The choppy, angular high-stepping left-to-right goosestep is a new style. I did runway modelling in the 70s. In those days, we were taught to glide with our chins up, our shoulders back and our backs arched so that our hips were slightly in advance of our knees. It wasn’t a comfortable walk, but it was graceful and dignified. The modern style looks ungainly and it must be awkward to learn. I don’t know how the girls these days pivot at the end of the runway without falling on their bums. I don’t think that the new walk shows the clothes off to better advantage than the old pelvic-forward glide did.
Doesn’t a pelvis-forward walk make your stomach pooch out a bit?
No, if you’re thin enough to do runway work, it doesn’t pooch out because your belly is already concave. There’s a way of arching your back and presenting your hip bones that I could demonstrate but that I can’t really convey in words. Maybe there’s somebody else here with modelling experience who could try describing the pelvis-forward glide? It’s an artificial gait, but not as ungainly as the new walk described in the OP. I did mainly bridal dress shows for a couple of wedding dress companies that used to have their manufacturing plants near where I grew up. (They’ve since moved their operations to China) but I also occasionally showed high-end honeymoon lingerie designed by the bridal firms. (I had to give up the undies shows after Dad, who was a puritan, put his foot down.) The scanties didn’t cover much of the stomach and, honestly, there was no pooching. Of course, that was when I when I was a teen; you bet there’d be major pooching if my middle-aged self tried it nowadays.
Your back is actually arched, so it stretches out the abdominal area eliminating pooch.
Also, as Sonia Montdore mentioned, runway models are rail thin - I once had a dresser comment about my hipbones “Damn - you could tune into a radio station with those things.” Yah - no pooch to be had.