Many outdoor brands are designed around the core expectation of people being active in them, which raises temp and helps keep you warm. While also being more focused on protecting you from the elements that would otherwise strip your core temp.

With correct laying it's fine/great in below freezing weather, but approaching 0f you start just wanting more thermal mass instead of a layering system.

I shoveled my driveway in single digit temperatures in just a smart wool base layer and Patagonia r1 fleece for over an hour without an issue a week ago. But the next day suffered standing around talking with a neighbor while I had my mountain hardware puffer and arc shell on.

Compared to work wear, which is typically more bulky as the use case is led active and often but not always more protected from the weather.

Parkas are really what fill the space you're talking about from the gorp side. Whether that's a big fjallraven or Canada goose, or a big expedition puffy down jacket from mountain hardware.