When you buy a car, the title is signed over to you, and you become its owner. Microsoft Office is information that Microsoft agrees to share with you subject to certain restrictions on your use of it. To actually purchase Microsoft Office the intellectual property, as opposed to a license for it, would cost you about 9 orders of magnitude more.

They're also restricting their customers' actions in meatspace (you can't drive people around in exchange for money) while the Office restrictions (you can't create business-related files) are IP-related.

A more accurate analogy would be if Microsoft banned you from using a Surface for business purposes (or for business purposes while running Windows, but it's impossible to install a different OS).

IANAL so I don't know if Tesla is on solid legal ground (I would guess that probably they are), but I think there's certainly a clear philosophical distinction.