Agreed, I was specifically talking about the desire for them to compose. I am familiar with legos absolute requirement on tolerances... which achieves what you mention.

But if I am going to buy all three of my daughters lego (which I have) knowing that they will not hold on to them for "decades" -- I'd rather they have a blast when they are a kid, and then move on to whatever, and the blocks can go into the ground without worry.

Yes, I am familiar with block exchanges etc... I have no desire to manage the post-market-post-play relationship I have with LEGO.

LEGO should be literally all over that service.

"Send us your unused lego and we will provide them to a nice farm Up-Site" sorta thing...

Can't you just buy from charity shops, and then give back when finished? The backbone of my kids collections will be my old Lego and stuff picked up second hand.