This is unlikely to happen.
The law prohibits you to from driving a car on public roads in certain cases. I don't see how it would be possible to prohibit you from legally purchasing a vehicle. Nothing has ever kept you from building your own roads and driving on it or driving on somebody else's (Like track days at a race course.)
The USA is committed to free trade and not allowing to legally buy a vehicle would have problems when faced with a constitutional test. Especially, the 14th Amendment, which states the following...
Amendment XIV - Section 1
All persons born or naturalized in the United States, and subject to
the jurisdiction thereof, are citizens of the United States and of the
state wherein they reside. No state shall make or enforce any law
which shall abridge the privileges or immunities of citizens of the
United States; nor shall any state deprive any person of life,
liberty, or property, without due process of law; nor deny to any
person within its jurisdiction the equal protection of the laws.
(emphasis mine)