Not just dreaming and fantasy, there's some actual numerical sleight-of-hand going on here. He's taking advantage of people's misunderstanding of compound interest.

Exponential growth will ultimately trump all other linear factors, even if the exponent is small. And that's also what makes small differences in that exponent so important (hence why computer scientists go through great pains to reduce complexity of matrix operations from O(2^2.51) to O(2^2.36)). Even if the investment only earned 1% per year, he can just sock it away in a 100-year trust fund:

    >>> 1000 * (1.01 ** 100)
    2704.8138294215287
    >>> 523 * (1.005 ** 100) * .45
    387.54342961962465

BAM - 85% "marginal" tax rate.

Plus, he has deliberately framed his scenario to take the maximum hit from taxes at every step. Corporate tax eats into his dividends? OK - invest in a growth stock instead of an income stock, and pay capital gains taxes when realizing the profits instead. Estate taxes steal most of the money from his heirs? How about he write a check to the university on behalf of his grandkids -- Uncle Sam won't see a dime of that.