Dell has been pushing Linux for like 20 years? I don't remember which distro, probably fedora or ubuntu...
I got an xps long time back that had the option to pay extra for ubuntu. I'm not going to pay to plug in a usb and I also get the joy of erasing a windows install from the face of this earth.
It's an option for maybe 2 SKUs... hardly pushing anything.
They have a very limited set of choices. I would have bought more if you were not too limited in term of choice in their inventory.
At some point the XPS 13 dev edition was the almost perfect laptop. Then they ruined it with the following generations of it.