Lol few years ago I got LBJ's from local library and made sincere effort to read through - it was humongous. I could not carry on after a week.

I dont really care if George RR Martin ever finishes Winds of Winter. But I will be immensely disappointed if Robert Caro dies before finishing the last LBJ book. He already somehow wrote 3,000+ pages in 40 years and hasn't even reached LBJ's passage of Medicare, Civil Rights, and Vietnam. He's 87 but still working on it apparently.

What inspires a person to dedicate their lives to such an intricate biography of someone else?

LBJ did some great things and he did some bad things. I can see that understanding and explaining how someone who had a life of immense consequence came to do both would be immensely valuable. That explanation could help drive the culture towards considering how we can get the former and avoid the latter as much as reasonably possible. If one was successful in that project, it is possible that their work would be more impactful in the long term than the person that they are writing about.

Also, some people are just compelled to do really deep work because they like it.

Caro dedicated his life to the study of contemporary power. He’s a fascinating figure in his own right.

IIRC, his wife is a scholar of medieval French literature/history and they do each others research.

Demand.

Is there a high demand for 3,000 page biographies?

"it was humongous"

Yeah, I've heard that too.

The audiobooks are also good.

I got a notification that the first one is on sale on Audible today for $8.