Or, like South America, we could have been numerous small countries headed by oligarchies, with all the wealth and power in the hands of a few families. Approximately 35 families own the entire country of Peru, for example. The outcome of the civil war ensured that the country would remain intact as one nation. The implementation of the inheritance tax prevented all the wealth from accumulating in the hands of a few families. To abolish the inheritance tax now, as the gap between rich and poor is already growing wider, would simply accelerate that process.
Money attracts money.
Before long, without an inheritance tax, they would own everything. To permit fortunes worth billions to be passed intact to a few in the next generation would eventually lead to a situation none of us would want. Enter words describing a concept or keywords.