The answer to that is vested interests and a government almost entirely staffed by fifth generation nepo-babies.
But maybe they’ll pull up the ladder if you ask nicely - it would be quite advantageous for them for your children to not receive your wealth, but for them to instead redistribute it amongst themselves and their friends.
And I say this as someone who fundamentally agrees with your point in essence, but can’t see a practical way that doesn’t involve the collapse of nations.