No, you don't seem to get it.
Your character doesn't have a "Body", your character is made out of Legos. To put it simply, once you equip a top that top is now "your torso", there isn't anything underneath it. So yeah, there are 1000s of different "models" for females cause each thing that replaces a body part is a model that makes up your character. What you're likely thinking of is rigs, all females other than lala's use the same base rig. But what makes up their body is legos of gear that the devs have to make sure fit well and act right.
Here is what YP had to say ..
"In a Fan Festival keynote speech, I stated that this will likely be the last time we add new playable races to FFXIV. To put it simply, a tremendous amount of time and resources are required to develop one. I’m sure you all understand that a new race will require new faces, hairstyles, bodies, and other assets. In addition to this, they need to be capable of equipping all existing items—this alone requires a massive commitment of resources. Each race has a unique frame and body type, and so every piece of visible equipment needs to be carefully adjusted to display properly on Hrothgar and Viera models. A cursory search will show that FFXIV has around ten thousand equippable items already implemented, all of which must be manually modified by our designers. This is an immediate and unavoidable development cost incurred when adding a new race.
The addition of new playable races will impact more than the development cost of the items added in 5.1 and subsequent updates. Not only will we be transitioning from twelve variations (six races, two genders each) to fourteen, but we will also need to commit more resources to the development of new emotes. While FFXIV will continue to strive to maintain a regular 3.5 month major update cycle, we must also ensure that sufficient time is secured for the meticulous development of new content—or else the quality will invariably drop. This is a complex problem that can’t be solved simply by throwing more money or people at it, as it impacts both debugging and QA.
In summary, these are the circumstances which informed my previous statement that this is likely to be the last time we add new playable races; as at this point in time, it is difficult to see us maintaining our patch update schedule if we have to account for more than seven races and two genders (technically six races with two genders and two races with a single gender, but this is the functional equivalent)."