Without a death tax you end up with a hereditary elite; even if you just consider it an income tax on the recipients, I have no issue with preventing that system from forming.
So you are a socialist.
With a death tax and a legal system that allows wealth above a certain level to be shielded you enshrine the elites.
Elites happen (like shit). If you can deal with that and not twist society and laws to try to prevent them you may find they won’t matter as much because new blood will constantly be added and those may be folks like the guys who started those great fortunes.
You know, people who frequently made fortunes making stuff people wanted, at a price they were willing to pay (in truth they WERE voted for on their way up, every time people chose to buy from them. It is mainly the bankers and lawyers that were not producers of value).
Not so. The four richest men in the US are self made billionaires. The majority of the top twenty are self made. The Waltons of Walmart fame are the richest family but that's because Sam Walton at a very early stage in his business career made his four kids equal partners in the business so they are actually first generation rich.
Gates and Buffet have pledged to leave the majority of their fortunes to charity which unfortunately will inevitably become controlled by left wingers (See Carnegie, Rockefeller and Ford Foundations)
The irony is that nobody was as much a hereditary elite as the Roosevelts.
It could be that TR thought that the inheritance tax would only hit massive industrial or corporate fortunes like Rockefeller's, Harriman's, and Carnegie's and leave older elites with their smaller fortunes intact.
If Theodore and Franklin believed that their background and position in society made possible whatever they contributed to the nation it seems a bit strange that they'd want to liquidate the fortunes that made their achievements possible, but maybe they thought their children and grandchildren would easily find careers in the growing government sector or elsewhere in the economy.
In any event, none of the subsequent Roosevelts rose as high as TR or FDR. FDR's kids more or less drifted after he died.
So you don’t want your kids to benefit from what you earned in your life. Sucks to be them.