Those can wind up deferring taxes, not eliminating them, and still they have exemption limits. The Roth IRA has contribution limits.

Gifts eliminate estate tax up to $12m. You can exceed even that limit by purchasing a property and placing it in a QPRT.

Life insurance trusts also have no limit.

Finally, even if it were true that it's merely deferring taxes, that means you can essentially time the market to pay less in tax when the rules are more favourable, and you can realize more gains in the interim.