Do you have any hints at what would make you consider him not stupid, historically? Being confident and narcissistic, and even talented at bullshit doesn’t make you smart. And recognizing weaknesses in the system isn’t really smart, even if it is perceptive, when those weaknesses are really just strong arm tactics that happen to be available to him through brazenness, inheritance, litigation, cruelty and others recognizing him as a convenient money laundering option.
There’s obviously been a drop in his coherence, but it’s not like he was smart and now he’s dumb… He’s always babbled bullshit at a 5th grade level at best, he’s just had enough money and undeserved confidence behind him that he could mostly muddle through an interview just sounding smarmy and punchable… Now he’s also dealing with dementia to the point where he literally can’t remember what he started bullshitting about.