They were a toy set first (inspired by variable mechs in Japanese Anime, e.g. the Valkyrie variable fighters Macross) and the original pitch of the series was as a means to sell initial line of toys.

So yeah, it would be much like if they made a TV series about Hot Wheels cars. That isn't to say it was of poor quality, just that the primary motivation was to sell toys.

So yes. the very existence of transformers emerged from a successful ad campaign. Deregulation of television during the Reagan era was what allowed this to happen during the early eighties.