The general audience can have some trouble getting behind things if it's completely "out there". It's not as bad as it used to be but it's something that used to be more of an issue. It's why Batman has gotten more love than Superman from general audience. People love the underdog and that's Batman. While Superman has his own struggles, his powers make them seem like not as big of a worry. It also helps that Batman's universe/world is more well known compared to any of the other DC comic titles. I'm not behind it fully but I do get why they might want to branch off with Batman films first.
What about that doesn't make sense?
Because that's not how it works. I've said stuff like this before, but--
Let's be realistic-- Batman, James Bond, John McClane,
The Karate Kid kid-- no matter how much the odds are stacked against them, or how much they bleed when they get hit, the audience knows full well that they're going to win. No matter how much better equipped the bad guys are, these "average joe" heroes tend to be hyper-competent anyway. Superman's got flight, super strength and speed etc etc... But Batman's a ninja, a scientist, a genius engineer and inventor, a multi-billionaire etc etc. McClane (Mr. Everyman, according to popular consensus) can take on 20+ terrorists every few years (practically by himself), take more punishment than anyone else, figure things out that every other cop in the city can't... and always come out on top.
Same with Superman, and Thor and whichever other hyper-powerful characters are out there. What makes these movies successful is how well-rounded the characters are, how charming or interesting they are, how successful and engaging the rest of the movie around them is.
You don't get points for just being "an underdog story"*, nor for either being grounded or out there-- these factors have there benefits, there drawbacks and are definitely important considerations, yes, but ultimately it's about being well-written and well-made.
A bunch of Superman (and Batman, and
Die Hard and
Rocky) movies (and comics, and books, and cartoons) haven't been well-received because they haven't been well-made. And the ones that
have been are the ones that made them icons.
There's nothing intrinsically saying Batman will forever be more well liked than Superman (other than
maybe dark brooders being a bit of an easier sell). Superman was far and away the more popular of the two for the first fifty or so years. He just needs a few good movies to get everyone back on side. NOTE: We're acting like Superman's hated, but he's still absolutely beloved-- just not as much as Batman, and not necessarily as well understood (which comes right back to years of poor writing).
*I put underdog story in quotes because, I mean... I can't think of a story that
isn't and underdog story in some way? I mean, lowly amateur Rocky must hold his own against the undefeated champ, sure... but Superman has to fight three super-villains who have all his powers! Batman's back is broken and terrorists are going to blow up the city! Thor's hammer is shattered and he's been thrown into gladiatorial combat! Lincoln might not get the support he needs to end slavery! It's more a marketing type than any kind of specific story. It's up to the filmmakers to create great adversity for the hero and for the marketers to sell it.
