It’s not that Irish, Italian, German, French and Russian people haven’t contributed to superhero comics especially as writers and cartoonists but that there’s nary their equivalent of Neil Gaiman, Alan Moore and Grant Morrison. Especially as the former. These aren’t unheard of, as Ireland itself’s Anglophone and those living in Northern Ireland are in a grey area. I suspect with Ireland, there’s nary a big equivalent of 2000AD even if there popular Irish comic strips before.
Similar for Russia to some extent. Now for Italy, Germany and France they already have major publications of their own, so far only Italians and just one French to my knowledge have illustrated for DC and Marvel comics. Though should there ever be their equivalent of Gaiman, Morrison and Moore it’ll turn out differently. Watchmen would feel very differently had it been written by a German.
Italian, French, Russian and Irish takes would be just as unthinkably divergent. So far Bubble Comics has a character (a redhead) who may be Black Widow had she been written by an actual Russian. I still think they could be far more widely divergent from their British counterparts with the Irish being the near-middle ground for these reasons.