If 343 does double down on publishing, it doesn't sound too bad of an idea, I've been demanding for years that 343 takes advantage of the IP and does a lot more quality spinoffs. Seeing other studios take on Halo's world will be interesting, in multiple different genres. But I worry what it means for mainline Halo...Maybe they will just outsource the development to another studio but stay in control of the story/creative, like The Initiative.
343 will significantly downsize in this case whilst focusing on Halo Infinite's MP with Certain Affinity but still retain a story/creative leadership team, like how Halo Wars 2 was done by Creative Assembly but the writing/art direction was done by 343...Perhaps we may see something like that expand to the mainline Halo stories.