Kirby's best work in the period when the seventies-eighties guys derided him, is probably in animation, because when he worked as a concept artist, here all he had to do was contribute raw ideas and let other people handle the details. Thus, things like THUNDARR THE BARBARIAN and CHUCK NORRIS: KARATE KOMMANDOS had stories, but that used the Kirby concepts to tell innovative adventure plots, instead of viewing the characters as an opportunity to be weird.
THUNDARR shows that Kirby's style transcends just craggy "Kirby wiggles." The cartoons looked almost Alex Toth-level polished, nary a wiggle in sight, but there was just something about the THUNDARR characters that immediately suggest "Kirby" despite the fact they're done in the Hanna-Barbera style. Nobody would ever confuse Thundarr for Birdman.
At Marvel, fans of the convoluted cosmic epics and sophisticated melodrama of the post-Roy Thomas school of Marvel writers objected to Kirby parachuting into the gritty, politically-charged (and to my current taste, hopelessly ponderous and pretentious) storylines of Captain America and Black Panther and taking over, injecting a Golden-Age sense of fun and action in his big, chunky style.
While I disagree entirely with that entire sentiment (the Englehart CAPTAIN AMERICA had a James Bond-esque spy groove reminiscent of a more contemporary version of Doc Savage - the Secret Empire, the Serpent Crown, the Falcon, and so forth; many critiques can be put against it, but a series with "Tricky Dick" as a super-villain is certainly not un-fun or even predictable) I *DO* agree with the essential stripped to the core point that you just made: that the reason many people didn't "get" Jack Kirby was because it was jarring to go from Englehart style science fiction adventure, to Kirby style acid trippery. It's like drinking a coke when somebody tells you it's a milkshake. OF COURSE people responded badly to it at the time.
In many ways, it was fortuitous you mentioned Kirby's CAPTAIN AMERICA, because Stainless is ying to the King's yang: Englehart managed to revitalize Cap by bringing him down to earth during the whole "Man Without A Country" stuff. Kirby pulled him the other way. Englehart does trippy stuff, to be sure (the guy admits doing lots and lots of LSD and pot in the seventies and eighties, making him one of the few non-liars of the Silver Age

) but the reason a moment like "Woman, you must MARRY that TREE!" in "Celestial Madonna" stand out, is not because it is common, but because Englehart's stuff is so otherwise grounded it stands out.
Englehart knew how to make fantasy elements stand out. For all the crazy stuff in his Celestial Madonna climax, Englehart wrote about the real Vietnam he as a veteran knew, down to using real GI patois. Kirby on the other hand, used art to suggest different worlds where fantasy elements fit right in: notice the Dr. Seuss-esque prehistoric world of DEVIL DINOSAUR.
Englehart was all about Captain America as a guy. The difference between histrionic posturing and suckerpunch powerful raw stuff is the difference between doing a belly flop and a perfect ten dive. Englehart did character-centered stuff, but IT WORKED BECAUSE ENGLEHART WAS TALENTED, he could make things feel real to the reader. Englehart's dialogue is snappy and beautiful and sounds like something people would say in real life. If you want to "get" who Captain America is, read Englehart.
Kirby's dialogue...well...he's the guy that wrote the most horrible self-introduction ever, even by the terrifyingly low standards of exposition-heavy adventure comics: "And ME, young but COOL Harvey Lockman!" Nightwing's critique was that Kirby didn't draw adventure comics in Neal Adamns realism - well, Kirby didn't do ANYTHING naturalistically; not anatomy (though he did give his figures a sense of solidity), not dialogue, not worldbuilding.
Characterization isn't as important for superheroes as it is for other kinds of stories, and you sort of expect gods to talk weird, but if you have problems depicting - my God - ENERGY realistically, you're in trouble. "Z-Ray." "Beams of Techno-Cosmic Force." "Cosmi-Current." What happened to good old fashoined infrared and laser beams?
But even here when we're talking about the various Kirby beams and rays, we see the strength of Kirby as a creator come the 1970s: he does little things, very subtle things that make us think that something he came up with is weirder than we could possibly imagine. For instance, Orion's "Astro Force."
At first, "Astro-Force" was a straightforward phenomenon: despite the pretentious title, it was pretty much some kind of death ray that came out of Orion's space exercise bike, right? Yes, UNTIL "The Glory Boat." There, Orion says, "They took all of my equipment...but not ALL! I can still CONTACT the ASTRO-FORCE!"
"Contact" the Astro Force? Don't you mean "fire," or "activate?" Just by changing ONE WORD, Kirby suddenly suggested that the Astro-Force was something vastly weirder than we had been led to believe. What IS the Astro-Force, that it can be contacted? I think my mind was just blown.