Fortunes above $10 million should be heavily taxed for that very reason, because reaching this level through work (which is taxed) is rarely possible, if ever.

Obviously it's not possible by normal (working) means. It's just not possible. 100$/h 100h/week would be 20 years, without taxes or cost of life. And not everybody makes 100$/h or do 100h/week.

Money like that is never made through wages (unless you're a football player or Taylor Swift, and they don't get paid by the hour). When I sold my first house, I made about 10 years income in one lump. The property tax valuation on this place has gone up over $1 million since I bought it.