Idk why you think your kids should get your money when you die. If they didn’t earn it then they should get a small amount and have to work for the rest, just like everyone else.
Did a charity work for my money? No. They just supposedly will (but possibly not) use some of it for something aligned with my interests. Just like giving my money to my children.
If parent’s work beyond what they can spend in their lifetime is not given to the children, who would continue to choose to work? Already in Canada you can exceed 50% tax rate and many adults who could see more patients, write more books, take more cases, do more work, choose not to as the marginal benefit decreases.