I think I've seen 90% of the movies mentioned here, which is probably a sad statistic. Could have done more with the political connections/disconnections that account for the fall part of the rise-and-fall narrative of these movies (surely it's more than the rise of CGI, with the dinosaurs killing humans--the culture shifted, in ways that books like Susan Jeffords's Hard Bodies trace well), but hilarious anecdotes aplenty, along with an unexpected and welcome (though thinner than I'd like) discussion of Jackie Chan alongside the white musclemen who dominated 80s US action cinema.
Best bits of trivia: Arnold took a whole bunch of acting lessons early on--like, really a lot of serious ones, and he devoted himself to reaching a certain level of craft, at least, with the same fanatical devotion that he spent on building his body; Bruce Willis read the entire Lord of the Rings trilogy 15 times; Stallone was and is a Poe fanatic who spent years daydreaming of making a movie about him; Chuck Norris is, according to this telling, a really nice guy who turned down all kinds of opportunities to act out in real life (he also taught Jessica Simpson to underact by instructing her to study Denzel's restrained deployment of his eyebrows); Steven Seagal, about whose real background we don't discover much (maybe nobody knows), was a power-mad scuzz with a mobbed-up entourage who "helped" him make movies (his legendarily nutso stint on SNL earns a brief recounting); Dolph Lundgren speaks five languages. Demolition Man, which I saw in the theater and loved, for some unaccountable reason, and which did not hold up on subsequent re-watch, apparently became a big meme during the pandemic, which I somehow missed. Most of these guys seem to have spent significant time inflating their egos, mistreating women, and/or indulging in substances way too much, with (it sounds like) Chuck Norris being the only exception, though Jackie Chan seems primarily to have bought himself a lot of stuff before one of his early near-death experiences on set sobered him up.
Also to cherish: the never-made concepts, ranging from horrific to missed opportunities. John Milius doing an Alexander the Great biopic, starring JCVD (maybe, though was he going to split-kick enemies in battle?); Seagal doing Genghis Khan (sure to rival John Wayne's The Conqueror in the annals of racist Hollywood caricature); Arnold in Sgt. Rock, opposite...John Cleese, which I think could have been kind of great. Is a rewatch of Commando in my future? Possibly. And maybe the Lundgren-directed Command Performance, which seems to be "Die Hard at a Russian rock concert." (Though the reviews are quite negative, so perhaps not.) Still, you can never stage Die Hard in too many different locales for my taste.
Update: I went back and watched Commando. God, somehow I'd repressed/forgotten/chosen to ignore how bonkers these movies were. Arnold, playing "John Matrix," from East Chermany, is introduced through 30 seconds visually caressing his arms (let's just say that we have ample time to evaluate the pumps in his delts, triceps, and biceps separately), and he lifts at various times: what seems to be an entire tree, a Porsche, a phone booth, and various bad guys. Also, whenever anyone gets shot, no matter where they are, they go flying backward, generally off a roof or through a window. The #2 bad guy looks like South African Freddie Mercury. Alyssa Milano plays Arnold's daughter, who's pretty capable, a regular chip off the ol' Matterhorn. Dan Hedaya, unfortunately, does not play Arnold's commanding officer or his buddy; instead, he is essentially in brownface yet does not pronounce the name "Velazquez" correctly. Maybe the best moment is when Rae Dawn Chong, along as the usual shrieking female sidekick (though she does also fly a plane), decides to free Arnold from a police van by firing a rocket launcher at it. Which of course works. I remembered at least four of the major kiss-off lines--and not just the canonical "I lied."