A fair point, but DB specifically implied they had not generated other galaxies. He never said Andromeda wasn't in the game, he said, "Does the Stellar Forge have the capacity to generate a second galaxy? Yes it does, it has the capacity to generate an infinite number of galaxies because we've just got to get all of the parameters right, but it's the benefit of that. Our galaxy is so flipping big, it's just so vast, that having an extra galaxy is fairly meaningless."
You could argue this is a non-answer, technically Braben never said they hadn't created another galaxy, but at the very least it's safe to put the galaxy theory very low on the tier list. If you watch any DB interviews you'll know that he has trouble lying. His three approaches answering a question are yes, maybe and no, all of which are delivered quite plainly; it's obvious when he's trying to be cryptic. Michael Brookes is skillfully vague and answers questions in ways that are designed to make you wonder what he's actually saying.
In the videos where DB talks about secondary galaxy creations he speaks matter-of-factly, as if he's absolutely sure that what he's saying is a simple answer to a simple question. There are none of the shady smiles, shrugged responses or playful airs he usually puts on whenever there's a mystery to be solved.