So for one that’s not strictly speaking true.
Just with Death of Superman. He didn’t stay dead, and neither did the relaunched electric mullet version of the character stick around long.
But a lot of elements did. The fact that he was dead for a bit is still part continuity last I checked. But either way Doomsday has remained a major villain. The associated introduction of a new Superboy stuck, and from what I gather he’s been more popular that Superman himself though mostly through team books. Probably more influential on Superman himself the Cadmus/genetic flippin about evil science thing has become a core part of whatever’s doing with Superman.
Likewise the follow-up I’m sorry Marriage of Superman thing has remained the status quo, ever since. Even progressing to the point where Superman currently has kids. The character shifted a lot of time towards a mentor/family man role.
They do have a bad habit of starting over, and supposed earth shaking events tend to not be. And it can be difficult to say that Death of Superman itself had lasting impact, since so much of the overall “Superman Dies” concept went down in a thousand other books, and for years after it had. Even once it’d been undone.
That’s all rooted in the publication model, and addiction to big cross overs and resets as promotional marketing.
For another Marvel and DC’s main continuity output. Is not synonymous with Superheroes as a genre. Nothing about Superheroes in general demands any of this.
You look a non-Big Conglomerate superhero series, like say Invincible. There’s very little “nothing ever changes” to that series. To the point where it’s exhausting how often they upend things.
Or Hellboy. Maybe less clearly a superhero, but definitely following similar beats and deliberately working the tropes there. It’s been going for damn near 30 years, multiple books. Many characters and different storylines (even different mediums). But none of that resetting and wheel spinning. Practically everything progresses or fleshes out something, and all of it stays.
Digest is not the publication model per se. It’s the physical format. That lil’ square book.
The publication model is books. It all runs through regular book distributors, very occasionally magazine distributors. Into where ever any kind of book is sold. The publishing industry rolls manga, industry trade paper backs/omnibuses whatever, and any kind of direct to book format comic into “graphic novels”. And they’re all distributed that same way.
The mistake Marvel, DC, and to an extent smaller traditional comics companies like Dark Horse and Image make. Is they look at Manga’s sales growth and say “we need more digest format comics”.
Instead of looking at their own TPB publications. Which are growing at a similar rate to Manga, out sell Manga by a hell of a lot. And apparently account for most of their profits.
They’re looking at superficial things like the page size, or that it’s Japanese. Rather than assessing the distribution model. So when they do do digest. They fucking fail. Except for Archie.