I don't think anyone outside Microsoft saw it that way later than 1990 or so.
From talking to microsofties, though, they had the underdog/maverick image internally at least until 2005. All the techies I knew left MS long ago, and all the business people I know at MS joined in the last 3-5 years and never bought into the "underdog" image.
The were the maverick to IBM's stodgy conformist.
Not that I saw them that way.