Weird thread title, huh? I tried posting on this subject a few years ago, but the thread didn't get many responses, in part because I didn't even understand what I was asking for. I had a hard time putting the idea into words. Therefore, I got very few responses. Hopefully I'll have better luck this time. The thread on Galactic Champions, where discussion turned towards Emperor Superman taking over and making the world a better place (why shouldn't he do it?), reminded me of this and so I wanted to raise the topic again.
So the basic idea is to look at Silver and Bronze age comics and come up with workable modern explanations for why things happen the way they do in those old stories. Come up with Iron Age-worthy explanations for why older, brighter stories could take place. Justify the happy world of the comics I grew up with to a modern, cynical audience.
--With the presence of Superman and other heroic characters always saving the day, there was no pressing need to force updated fire codes, or improve airline safety. There's always some burning tenement building in Gotham or New York or wherever, because the local superhero always saves everyone. You haven't had those disasters where 200 people burn to death. A headline that says "Building Burns in Hell's Kitchen, Zero Dead Thanks to Daredevil. Molly the cat missing." doesn't generate near the calls for political action that you saw in the real world in the mid-20th century. So there's always some kind of emergency for the heroes to react to.
--In the real world, huge increases in violent crime in the late 70s through the early 90s led to a "tough on crime" approach that saw incarceration skyrocket and police use more aggressive tactics. In the 60s and early 70s it was not uncommon for murderers and other criminals to receive shorter sentences, or often be placed in mental hospitals (compared to today). Many courts were also more likely to use the exclusionary rule to keep out improperly obtained evidence, the whole "bad guy goes free on a technicality" thing that you've heard about. When Bloods and Crips started massacring each other in the 80s (and then all the crazy meth-related crimes of the 90s), courts became much more conservative and far less likely to do that. If superheroes are present, that spike in crime may never occur, leading to the "revolving door" that lets supercriminals back out of jail.
--Investment into super-technology has led tech development in a different direction than in the real world. iPhones and internet are less important when people can build flying robots and things of that nature. Tech trends towards big and bold industrial scale instead of small consumer oriented devices. The Batman Animated Series villain HARDAC is a great example. It's a super-computer 80 feet tall that is self aware and can shoot zap bolts. That's cooler than Angry Birds. The justification is that when people have super-powers, the investment is going to go in the direction of countering and/or duplicating those abilities. This also means less money for things like ever-present security cameras, or facial recognition software.
--More tolerance for vigilantes and known "good guys" because of the prevalence of super-crime. Mind control rays and extradimensional evil twins are a proven thing. People know they exist for a fact. So when Batman, who has defended his city for 10+ years, suddenly goes on a week-long crime spree robbing banks, once he "gets over it" and starts being a hero again, no criminal charges get filed. Batman tells the cops that the Joker used a hypnosis ray, and everybody says okay and just believes him. After all, everyone remembers last year when half the city got hit by a hypnosis ray and spent the afternoon thinking they were chickens. Known superheroes are going to get the benefit of the doubt in almost all situations, because everyone knows they're the only ones who can really stop some of these villains.