No. Not all fitness models eat lean high carb diet and do excessive cardio. In general, if you do a heavy duty exercise regimen you will be either needing more carbs or can do it in very low carb mode. Some people can, some can't. With the model look, they need their muscle to 'pop-up', so they do need some carb (to hold the pump).
To grow bigger muscle you need to overeat, and most muscle growing regimens will involve increasing carbohydrate, either part and parcel, as carb-ups, or continuous. Multiple meals a day with high protein intakes is a normal muscle growing routine. They go low fat so they can keep calories low enough and not to gain too much fat at the same time. You are less hungry with more fat, fat loss is more efficient with low fat.
Normally, women need more cardio than men, because the muscle are smaller and the natural fat layer is thicker + infamous stubborn fat on the low body is hard to mobilize. It is harder for women to bulk and cut because muscle gain is low, and fat gain is high, and fat 'sticks'. Even women who lift insane amount of weights and are crazy strong can't get those pretty muscles like men do unless they are genetic powerhouses or take hormonal drugs. Those models also fasted for ~ 2 days before the shoot as well & prepped for it for a few months by reducing body fat.
Can anyone achieve Oxygen model physique even if they are super-dedicated? No. Genetics is a huge influence. One is not predestined to be fat, but she can also be prevented from becoming 'cut' by the fat deposition pattern, the ability to channel calories to muscle, the hunger tolerance and the sensitivity to stimulants (both food and drugs).
A woman who is naturally slender will be slender if she eats pasta with bananas and hot chocolate and does a couple of bicep curls after running around the park for 3 hours a day.
The achievable goal is being the best you can be, doing minimal amount of whatever rocks your boat and gets you 80% of the result. Apparently some women in Russia are willing to be bed-ridden for 4 months to have their legs broken and reset to gain an inch in height. There is a level of commitment which is simply absurd if you are not intending on a professional carrier and gives no satisfaction.