Maybe I'm missing something, but I think you've got it wrong.
Winston didn't get out of NASCAR because of government intervention but, in fact, government intervention is the reason Winston began sponsoring NASCAR in the first place.
Quoting Wikipedia:
"NASCAR's top series, the NASCAR Grand National Series, found sponsorship from R.J. Reynolds Tobacco Company (RJR) in the early 1970s following the United States ban on television advertising of cigarettes."
and
"On 5 February 2003, R. J. Reynolds informed NASCAR that their five-year extension to sponsor NASCAR's premier division signed in July 2002 could be dissolved because of economic concerns at the company."