I learned something new about Mexico (was researching Indigenous)

[XDKrieg33]

One the reasons was that mesoamerica was more populated than the rest of north america, so they didn't need to bring settlers to their colonies to work the land since they already had the native work force.

One of the places in which they needed to bring european work force to new spain were the jalisco highlands since they couldn't conquer or reach an agreement with the native of the region (chichimecas), so they decide to annihilated them.

And the reason why the spaniard couldn't conquer the chichimecas was because the chichimecas were a nomadic group unlike the aztecs who had a state structure.