The Declaration of Independence is in the style of an oration, not a conversation. People definitely use more complicated sentences than that in conversation –

The Declaration of Independence is in the style of an oration, not a conversation. People definitely use more complicated sentences than that in conversation – heck, I’ve had conversations where 4 different running threads were intermingled ad-hoc, and both participants were able to keep track of all four ongoing thoughts just fine – but not in the same high and formal style. (Some orators still use such a style, but probably less than 50+ years ago, as audiences have changed.)