I've begun gradually giving my ~30-year-old childhood Legos to my son, and am impressed with how well they've held up. I haven't noticed any yellowing or fading

I've begun gradually giving my ~30-year-old childhood Legos to my son, and am impressed with how well they've held up. I haven't noticed any yellowing or fading. I wonder if the new plant-based plastics will have the same longevity.