How big is the dynasty trust market?

Bigger than I thought. Guess a number before proceeding.

For those who are not familiar with them, Dynasty Trusts are perpetual private trusts. Under the common law, only charitable trusts were permitted an infinite life, while private trusts were governed by the wonderfully intricate "rule against perpetuities." As a practical matter, private trusts usually could not last much longer than a century. Which, one might think, should be plenty.

But the era of very high estate tax rates created an incentive to make trusts last longer, and so the Dynasty Trust was born. Several states reformed or abolished their rules against perpetuities to make such arrangements possible.

The strategy has born fruit. SSRN-Jurisdictional Competition for Trust Funds: An Empirical Analysis of Perpetuities and Taxes by Robert Sitkoff, Max Schanzenbach reveals that according to banking records, through 2003 about $100 billion has been placed in Dynasty Trusts. Interestingly, states that abolished their perpetuities laws but retained income taxes on Dynasty Trusts did not share in the bonanza. Thus,states do not share in the good fortune driectly through tax revenues, but only from the greater employment associated with trust management.

If the estate tax is repealed, will the market for Dynasty Trusts wither? Or is the urge to leave a permanent family financial legacy strong enough to sustain them without tax benefits?