I saw this circulating again, too. Seeing how the rumor has kept going for what, 3 years now? It seems really clear that this project has been in development for some time. And I think that they have been deliberately taking their time to develop projects the right way, despite Bob Iger stating that Disney wants to release a new Star Wars film ever yet.
I think in this case Lucasfilm wants to keep the Obi-Wan project under wraps until they're absolutely ready to go public about it. In large part because I think they're trying to right the ship. There was a somewhat polarized reaction to THE LAST JEDI. They had to bring in a second director to re-shape ROGUE ONE, which we only learned long after the fact. They had two successive projects that had director changes in varying stages of production (Solo and Episode 9). And on top of that there was the Josh Trank/Boba Fett debacle where that project got shelved. I think Lucasfilm is being a bit more guarded given that track record.