I remember this one being discussed about a decade ago when it seemed like an interesting but relatively self-contained culture what-if. Nowadays, of course, we know it would drastically change the shape of 2010s cinema.
Alan Moore's career is massively butterflied if his first attempt at making anything for a major American publisher ends in the company being sold to Jim "Direct Rule from the Bullpen" Shooter and the new direction he's taking the comic dies an ignominious death.
Given how much this could disillusion Moore, there's a high chance he a) refocuses back to Blighty and becomes a 2000AD stalwart, opening up the possibility of something like The Ballad of Halo Jones becoming, if not his magnum opus, at least one of his major works;
or b), he gets majorly involved in the indie black-and-white boom out of a "fuck-'em-all" spirit and we end up with something like Promethea, only decades early and before he's totally disappeared up his own beard, and also printed without colour in Dave Gibbons' garage. Perhaps Alt!ABC becomes a major indie player alongside Eclipse?