The Maya are still around, but the Maya civilization's institutions were all destroyed. And the Spanish made a point of seeking out all the Maya books [1] they could find and burning them. So a lot of knowledge was lost.

[1] https://en.wikipedia.org/wiki/Maya_codices

I was surprised to find out that there are still many indigenous groups with populations in the millions. My California public education made it seem like they were all pretty much wiped out save for those who survived to the various reservation systems.

My favorite group is the Mapuche who managed to hold out against the Spaniards until they were conquered by Chile and Argentina in the late 19th century. They managed to thwart the conquistadors for centuries! It wasn’t until the modern era where military logistics got good enough to unseat them and overcome the advantages they had.

I've been in towns in Mexico where the kids ONLY speak a Mayan language. No Spanish or English.

I asked for directions and just got blank stares until someone who spoke Spanish in the village explained, lol.

That is not that simple. They never invented the wheel, the Maya calendar cycled over 5128, which is not really convenient, numeric system was also rather uncomfortable, strange numerals working in 19-base system (but they have invented zero). In addition to that they've invented sadistic religion with human sacrifices and their culture was very aggressive, what finally put Maya civilization to an end, as everyone around happily joined European conquerors to get rid of Mayans ASAP.