I was surprised to read that he gave an interview. I think up until a short time ago he was still working on the newspaper strip. I did a little googling and I found an interview Lieber did with Roy Thomas in his Alter Ego magazine at TwoMorrows. He does give Stan a lot of praise here and I get no sense of bitterness from it. But it is from 1999. He goes into a lot of "behind the scenes" information. He does go into some detail about Stan asking him to give Jack some scripts to draw. Quite honestly, I never knew that Larry Lieber wrote the first Thor stories and came up with the Uru hammer, which has nothing to do with the mythology. Roy Thomas later looked up the the name from the Norse myths, Mjolnir.
I really don't see how you can think that calling someone blue-collar is an insult especially as I come from a blue collar family. My paternal grandfather was a Polish immigrant who worked as a janitor in the steel mills and my maternal grandfather was a train engineer in Great Britain. Some of my aunts and uncles never even finished high school because in the Depression they left school and went to work instead. Jack Kirby was a product of the Depression also. His family was poor and I remember him recounting how he would draw on the walls of the building. He never had much formal training and found work as a teenager. Most bios say he left high school to go to work so I would guess he never even graduated high school which was common during the Depression. Children would go to work to help the family.
I think there is one common trait of both Lee and Kirby is that in their younger days they did read some of the classics, probably as part of their high school assignments but also went to a lot of the movies. Later in life, Kirby was very interested in the more speculative things like Chariots of the Gods (1968), etc. He probably drew upon that for things like the Eternals and the New Gods, etc. Of course, Kirby was already going for the cosmic with Galactus and the Silver Surfer. So anything along those lines I would credit to Kirby as the source.
If that is the kind of thing that Rieseman uses in his bio then I don't respect that very much. Fellini was very art house and his films never got general release in the U.S. My sense is that Stan would be very old school and wouldn't have sought that out. he has mentioned liking things like the Three Musketeers (1935) in his film going days of his youth.
I also have some issues with this revelation about the films . For one thing, we know Stan was having issues with his vision at this point of his life. We don't know how long he'd been having it but I suspect it goes back to as long as his tendency to wear tinted glasses. He did finally reveal in 2016 he could no longer read very well. I had seen photos of him holding something very close to his face to read them. And we're talking about an elderly guy in his 80s and 90s when the MCU really took off. Sometimes there is an issue with short attention spans. My mother was getting like that at that age and would constantly use the remote to change channels because she lost interest in things very quickly.