Tesla has had billboards all over LA and SF for many years now, so your definition of advertising must be very different from the normal definition. Any company following GAAP (standard accounting practices) would also consider stunts like the "flame thrower" and the Roadster in space to be marketing activities.

The only marketing activity Tesla hasn't actually used is paid TV commercials, unless you include Hulu or online streaming, in which case... Tesla has actually used every mode of advertising commonly used by its competitors.

The fact that Tesla doesn't actually categorize its marketing activities as marketing in its financial statements just means that Tesla isn't following GAAP.