I’m sure they had trusts, but we already know they held real estate in their personal names. Their estate is no doubt complex, and they may have testamentary trusts. Very few wills, even amongst the wealthy, put the entire estate into a testamentary trust. What is your source for your assertion that most wealthy people do so? That’s not suggested in the article.
I am not that knowledgeable about trusts, but the few wealthy people I know have trusts to manage all their assets. The trusts that I am aware of were created because they wanted to ensure that the money/assets are protected from creditors, martial breakdown, present and future spouses etc.
The beneficiaries to the trust are unable to change or modify the terms. The trustee controls everything and will follow instructions given in the trust as to how all the assets are managed.
It is my understanding that personal property can also be included in a trust. I will ask one of my close friends who have a trust and how it relates to their residential property.
Perhaps someone is more knowledgeable than I am.