Orion's mass far exceeds Heavy's payload to TLI. It simply can't be used for the Artemis manned lunar program unless you want to completely reengineer the entire thing.
This is incorrect. NASA even carried out an internal study on this exact topic. [1]
Everything NASA does is trying to shoehorn in Boeing one way or another because they have tremendous political influence, but there's really no reason for them to be involved at all from a technical point of view. And in fact if they weren't, then we indeed probably would have long since already put boots on the Moon again. But because they are involved, I suspect an appropriate timeline for success is: never, with a whole lot of money spent getting there.
