See my reply to icon_uk above. A Rogue's Gallery is one thing, an army of normal human soldiers could handle that (even if the battle would probably have a much higher body count). But when it comes to sudden intergalactic threats to the whole world, you need superhumans.
Also, I add that Batman isn't really a good example of human skills making up for lack of superpowers, because his skills have been overblown to such a ludicrous extent that he effectively doesn't really count as human anymore. There is a reason Fandom nicknamed him Batgod. And even then, he only fights the really big threats with the help and backup of the Justice League.