***Sometimes old habits die hard.***
Hundreds of years?
Sounds more like Rome selling out to collect tithes from the pagans than converting them.
There's no such concept as "tithing" in the Catholic church. You can go to Mass every day for your entire life and never put a penny in the collection basket, and nobody would care. Nobody's counting.
It may have escaped your notice but we've been trying to convert the world to Jesus for two millenia and are not there yet. Not by a long shot. Four hundred years (Mexico) is a relatively short space of time in comparison.
Pagan traditions in Mexico and elsewhere in Central America go back thousands of years and long predate Christianity.