I mean personally I think if e.g. pornhub were to launch a product like that, they should make sure that it's not associated with PH or pornography directly. That creates a stigma - "oh, it's that porn blog" - which in my outsider's perspective was never Tumblr's identity.
This also raises other questions:
What is the difference between Pornhub and a pornographic Tumblr?
What is the essential demand behind the demand for a pornographic Tubmlr?
A very interesting phenomenon is that since Tumblr announced the ban on adult content, many bloggers have turned to Twitter instead of Pornhub.
Pornhub is like a swamp, content wise.
Porn = male gaze-y, intentionally and overtly about sexual gratification, less about exploration
A free-wheeling blog site = a place open to the exploration of a number of different aspects of identity, of which sexuality is one of them.
In short: If Pornhub were to create a tumblr clone, they'd inherently be enticing people to _produce porn_ rather than producing content which might happen to be somewhat pornographic. There's a huge mental barrier there for lots of people, even if they happen to enjoy viewing porn or producing sexually explicit imagery.
 Yes I know women watch porn, the default assumption of porn viewership is still a cis male audience
>Pornhub Premium launched in 2015, and now has more than 1 million signups. That's nearly the number of people who subscribe to the Showtime channel's streaming service.
>According to various reports, currently, the porn industry’s net worth is about $97 billion. This money is enough to feed at-least 4.8 billion people a day. Every year, Hollywood releases roughly 600 movies and makes $10 billion in profit. And how much porn industry makes? 13,000 films and close to $15 billion in profit. The porn industry makes more money than Major League Baseball, The NFL and The NBA combined.