Star isn't "speculation." It's an officially-announced platform, set to be a "hub" of Disney+, which will sit alongside the Marvel, Star Wars, Nat Geo, etc hubs at the top of the screen, and will house all of their adult content (i.e. most of the 20th Century Fox library). This is a fact and something that *is* happening. The are countless articles all over the internet about Star, with screenshots and everything, centered around Disney's official announcement of the platform earlier this month.
However, I just did some more research, and learned that Star, as of now, is only launching internationally in 2021, in basically all territories that aren't the United States, where Hulu doesn't exist. For now, in the U.S., Hulu will remain the adult content platform for Disney's adult fare. So...
-In the U.S., Hulu = Disney's adult fare
-In the rest of the world, Star (which will reside inside Disney+) = Disney's adult fare
That said, it sounds as if Disney will eventually dissolve Hulu in the U.S. and adopt the Star moniker/strategy here as well, potentially in the next couple of years, so everything is under one roof, all over the world. In other words, the global rollout of Star in the coming months is likely a preview of what's to come in the U.S. And either way, they ARE "stepping to HBO's corner," starting in February, at least internationally. It's not official yet here in the U.S., but the writing's on the wall...