I don't have kids, but if I did, I would probably not go for Lego but for 3D-Printing.
It shouldn't be hard to print pieces that can snap together. In all kinds of colors and all kinds of forms.
I imagine the adventure of printing new pieces would be a fun thing for the kids and the parents. And when the kids are old enough, they can print pieces on their own. And a bit later design pieces on their own.
Would there be any downside to this approach?