Gerry Conway or Archie Goodwin stay longer than their handful of issues on Marvel's Tomb Of Dracula, so Marv Wolfman doesn't join and go nuts with it.
1) Teenager Dave Olbrich has one less comic in the handful keeping him interested and he drifts away from the hobby. Olbrich never joins the nascent Fantagraphics:
ai) Without someone of Olbrich's skill as sales manager, Fantagraphics may not last too many years in a difficult industry - that means The Comics Journal to continue banging the drum against how creators are treated in the 1980s and specifically about how Jack Kirby is treated, and less force to help undermine Jim Shooter & cost him the EIC job.
ii) Jim Shooter's continued presence at Marvel means no Valiant Comics, which may also mean less other publishers going "hey we should do that"; he'd also be more likely to resist the demands from on-high for uber-variants and eternal crossovers, which delays the speculator crash a few years.
iii) Marvel under Shooter found it harder to bring in or retain the more flashy or odd creators, and if this goes on for a few years it means Todd McFarlane, Rob Liefeld etc end up/stay at DC. No X-Force or X-Men "Gold"/"Blue" era in the 90s, no Cable or Deadpool - thus
iv) No Deadpool and Deadpool 2 in the cinema right now, so no irreverant R-rated hero-comedy to influence other franchises
bi) No Fantagraphics - comics like Love And Rockets will fall out of print until someone else picks them up.
ii) No large, obvious publisher waiting to publish Chris Ware's works - they may not exist - or My Favorite Thing Is Monsters, Black Hole, Hip Hop Family Tree etc. A lot less variety.
iii) Fantagraphics doesn't pick up Usagi Yojimbo, so it doesn't last long. No Usagi Yojimbo to appear in Ninja Turtles
bi) The 1980s saw less drum banging for creator's rights. That means the artists that would form Image Comics as far less likely to because it's just not in the air. Thus no Spawn, Youngblood etc...
ii) No McFarlane Toys to influence on the collector's market
iii) No Image Comics means The Maxx, if it exists, isn't from a big company. Thus no cartoon of The Maxx on MTV, thus its influence is cut down.
iv) No Image means no The Walking Dead which means no huge success for AMC from The Walking Dead TV show, also a few less zombie stories in pop culture.
v) No Image means a lot less independent creators working.
c) Olrich started the Eisner Awards. They're gone.
di) Olrich was poached from Fantagraphics to help Scott Rosenberg create Malibu Comics. They don't exist
ii) This means Will Jacobs and Gerard Jones don't have a career break writing a comic for Malibu, which upends their careers and means Men of Tomorrow is never written, and a lot of what is known about the history of Golden Age comics is not. (They're fine at Lampoon though) Potentially not being a big man in classic comic circles means Jones is less able to get away with paedophilia for so long.
iii) Malibu never publishes Evil Ernie and begats Chaos! Comics, thus no Lady Death et al and the "bad girl" comics of the early 90s are far less of a thing.
iv) Malibu helped drive computer colouring - it distributed early Image and ran a colouring program that Marvel really, really wanted. It'll win out eventually but take longer to be ubiquitous, changing how a lot of comics look
2) Blade is never created
a i) No Blade film, so no successful Marvel comic film in the late 90s that likely makes people think "I can make a bit more cash here" and leads to other films
ii) Less superhero films in early 2000s means no Marvel Studios and their cinematic universe in later 00s - thus entire direction of Hollywood is changed.
b i) Blade II is Guillermo del Toro's second US film after Mimic and is what really brings him to Hollywood's attention, so Pan's Labyrinth is a much cheaper film without Doug Jones in it, there's no Pacific Rim, Shape of Water etc and del Toro is still mostly doing Mexican horror. Any influence he has in the industry is undone.
ii) Del Toro is never attached to The Hobbit, which means the studios (as it appears) don't get cold feet about his approach - whoever they do get is more inline with what they want. Peter Jackson is not forced at the last second to come in and do it, so production goes a lot smoother
iii) Smoother Hobbit production = earlier production. This may mean the studios can't imply they'll take production away from New Zealand over a union dispute (they're already making it!), so the New Zealand government doesn't alter the law of the country to placate Hollywood companies, which means NZ production crews may or may not get less work in total but they'll get better pay & conditions for their work, making their lives a bit more stable. This might benefit the local film industry as Hollywood isn't competing with it for all the resources, or may not.
iv) If less work in total, some other country is getting that work and a lot of jobs are happening.