Dell has reiteratively announced Linux-based products over years without coming to any serious model out.
I think there is a powerful reason over that: Linux is free.
Buying a good Dell computer with Linux means it wont have Windows, so if somebody wants later to go to Windows, it would be way more expensive to buy non-oem licenses for it.
Counter wise, if you buy a good Dell computer with Windows, you get a “good price deal” for the OS, and if some day you want to migrate to Linux… it is free.
Of course, there are other reasons… other heavier reasons, I still don’t understand… Maybe a MS anti-competence policy that ties Dell?
