The conclusion of Avengers vs. X-Men brought on the renaissance of mutants, undoing House of M/the "No more mutants" spell. They could have done it then. A bird in the hand is worth two in the bush. Why wait for more to happen?
Even before the conclusion of Inhumans vs. X-Men, the debate was that mutants belong amongst the humans, and they shouldn't separate to live elsewhere. They later went elsewhere: Krakoa, Earth's moon, and Mars.
Maybe the plan was for the mutants to have more reasons.