That’s the reason why so many Mexican immigrants don’t even speak Spanish - they are the literally poor indigenous that Mexico doesn’t want and can’t assimilate.
We’re their social pressure relief valve.
Sorry, but that is baloney.
The Mexican government set out on a HUGE literacy quest for ALL Mexicans, WAY back in the 1950-60's. Mexicans ARE literate. The poor indigenous CAN read and write.
OFF-TOPIC:
I remember visiting the Yucatan Peninsula way back when. There had ALREADY been Catholic priests and nuns who had been there ahead of us, WAY ahead of us.
They came into the very (then) isolated area on MULES.
HORSES were big and strong but were frightened easily with gunshot...NOT the bravest of animals. They would not protect their riders and would run away at the sounds of gunshot.
BURROS/donkeys were small and strong and were frightened of NOTHING. But they were too small for riding. They were fearless but way too small to be useful for the riders.
The hybrid: MULES.
MULES had the size and strength of horses and the disposition of burros/donkeys: PERFECT creatures for the Catholic priests and nuns. Those mules PROTECTED their riders and would NOT be intimidated. THEY would fight back!