100 shares of BRK-A in 1980 would have been about $30,000 for your parents to buy. They paid tax on the $30k. You inherit those today and they are worth about $30 million. If you make the argument that one should not pay tax on this inheritance, fine. But don't pretend tax was already paid on the $30 million. How about at least a capital gains tax before a tax fee transfer?