When you are creating a new product there are 2 kinds of marketing activities: the easy ones and the hard ones.
Easy marketing activities: sales teams, press releases, shiny brochures, new websites, SEO, social media efforts, etc. Most of the time these activities just serve to the egos of non-customers, partners, the board, the entrepreneur, and industry pundits.
Hard marketing are activities: these engage customer, finding them, crafting a solution for them, making easy to buy from you, and being a trustable vendor. This is Product Management.
Engineers use to hide behind and don´t show up to the customer. But without users or customers and their daily feedback there´s nothing.