I fly GRU to the US for decades every year and in the late 90s and early 2000s we would always have severe turbulence crossing the inter tropical convergence zone. I have not encountered that kind of turbulence for at least 15 years. I guess technology got better and they're able to avoid it most of the time.

Now when I do this trip with kids I tell them they have no idea how bad turbulence can be since they never experienced the roller-coaster type of turbulence where you feel like you're falling for several seconds.