I guess it is just your point of view of what is rich or not but considering that - 1.3% of all estates are $1 million dollars or more. That says to me were talking rich people.
I am not sure what you define as rich but when your wealth exceeds 98.7% or more of the entire US population you look wealthy to most people.
It certainly appears rich, but remember that as we move to 401(k)s, which can be passed on, from defined benefit pension plans, many people--at least those with the foresight to plan well--will have larger estates ($1 million is a decent-sized, but not huge, 401(k)). Also consider that with property inflation in many parts of the country, ordinary houses can fetch $500,000+.
Together, these mean we will probably see far more estates in the $1 million+ range, even from people with middle-class incomes.