I was hoping it was a typo, and they actually meant 4 and 5... I didn't even know people made products that still use ddr3.

Especially industrially, ddr3l is just fine. At a certain point you don't need the speed of newer generations, and buying new idk lpddr5x/t controllers for 30 year old process nodes just isn't worth it. Until ddr3/l to EOL from everybody. The big 3 aren't the only memory fabs.