It has not turned out like that.
Public figures are primarily interesting for what they publicly do.
While we will sniff at the air to catch the least whiff of corruption, while we will rake over the family ashes to discover the ember still glowing with the itch for power, the secret engine of desire, what most of us want to know is how they got power, how they used it, how they lost it and what they achieved or failed to achieve by it. That yields us antecedents, rises, achievements, influences, with a side-trip into 'Family Life' and a bob to the ladies. Political biographies are not a growth industry. By contrast, over the last couple of decades the literary biography has not only been cantering away from its political brother, but routinely outselling all other forms of narrative history. The reasons for this vast public appetite are mysterious.