I may be a pessimist, but my perspective is that unless there's a vision for how a new user has a good experience once they're here, advertising and PR to attract new users would largely be wasted money. A while back I tried to convince people who share my hobby to try out blogging on Steemit: some rejected it immediately when they didn't see any content they found appealing on the Trending page which they were seeing, some gave up when their accounts took forever to get created (this may be fixed now?), and others gave up when the rewards system didn't seem rewarding enough. My conclusion at the time was that there was no point in trying to convince people to come here unless and until I had a reasonable expectation that they'd have a better experience (for example, me having enough SP to give content I value a nice upvote myself without hoping for an audience for niche content to materialize from the ether).

There is more to marketing than advertising and PR. The essence of marketing is figuring out what story you want the customer to believe, and having a product that enables people to believe that story. To me that seems more like it's about the vision for the ecosystem and the features the platforms provide than it is about advertising or PR.