Tocqueville identifies the division of estates and fortunes as essential to equality and democracy:

But the law of inheritance was the last step to equality. I am surprised that ancient and modern jurists have not attributed to this law a greater influence on human affairs. ... When the legislator has once regulated the law of inheritance, he may rest from his labor. The machine once put in motion will go on for ages, and advance, as if self-guided, towards a point indicated beforehand. [0]

The whole passage is worth the read, and well supports your point that the effect of inheritance taxes is both societal (smaller estates) and individual (different incentives for wealthy progeny)

[0] https://play.google.com/books/reader?id=xZfiBEzcPTEC&printse...