It's amazing how much we can tell about not just a person, but their society from clothing found like this.
We know they had sheep, we know their domestic economy meant that they had sufficient to over Winter sheep to be able to shear decent fleece, and not simply kill them for meat. That also indicates that they had milk from those sheep as was common in agricultural societies of their time. Milk makes cheese, and cheese is a long lasting protein staple.
So they're not living hand to mouth.
We also know that they had a society stable enough for them to construct and weave on warp weighted looms....that needs woodworking skills as well as textile ones, and someplace to put it up and keep it up while it's being used.
The weaving is not a basic tabby weave, it's a complex pattern, it's an accurately symmetrical design, with carefully chosen colours. The spinning is very good, consistent, etc., and though the garment seems simple, it is both comfortable (mind female)practical, adjustable (mind female/pregnant, non pregnant) and enduring. It's also quite smart, very neat looking in wear.
So, very much not a primitive society, very much a farming and hunting and very capable society.
There's also the aspect of preferential preservation. All that has been preserved is 'animal' in origin, but the lack of an undergarment above the skirt might simply be that any linen/flax/nettle cloth simply rotted away in the bog.
The bog tannins preserve wool, hide, hair and leather very well indeed.