The team responsible for DX11 client is likely also responsible for the DX9 client, which also needs enhancements and fixes to support new content.
The team responsible for models and textures and associated resources to complement the DX11 client, also need to work on new resources for new content.

Even if there are plenty of teams involved, it's not likely that they have separate teams that work on textures for DX9, DX11, PS3, PS4...

When it comes to textures and models for new content, they likely prepare it for the DX11 version right away now, even if they didn't do that for 2.0.