Most wealthy people have the estate set up as a trust. I would think BS & HS would have set up a trust.
https://www.theglobeandmail.com/globe-investor/personal-finance/taxes/the-top-10-reasons-to-set-up-a-trust/article16832572/
Im 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? Thats not suggested in the article.