Part of it also has to do with the fact that it is two different writers, and one writer is already spoiling the other’s story.
HoX/PoX had one writer in Hickman, mystery as to how they connect, and mystery as to whether success/failure in one book will affect the other book. Readers felt the need to read both books, or miss out on interconnected tidbits.
Here, we have two writers, with no mystery that Duggan’s mutants are destined for failure since Gillen’s future happens . Since it is two writers, we have no confidence that they will be very interconnected. So in effect, nothing that happens in Duggan’s book matters; the only book to read is Gillen’s.