Stuck in the Past

As I've no doubt explained previously, I was never much of a comics reader as a kid – or, more precisely, I was never much of a superhero comics reader as a kid. With the exception of Doctor Strange, Master of the Mystic Arts, which I picked up intermittently, the two comics I followed with any devotion were both science fiction titles, Star Wars (about which I've written many times before) and Micronauts (about which I don't believe I have). 
Nevertheless, like all American boys growing up in the 1970s, I was still very much aware of superheroes, thanks in no small part to their TV and movie adaptations, including cartoons. Perhaps because he was Marvel's most popular – and merchandised – character at the time, I had a special fondness for Spider-Man. I loved the terrible 1960s cartoon, which I saw in reruns, as well as the equally awful 1977 live action series, starring Nicholas Hammond of The Sound of Music Fame. I also remember watching the Adam West Batman series, various incarnations of Super Friends, the 1978 Superman movie, and probably others I've long forgotten. As I got older, I retained a vague affection for the idea of superheroes, especially after I started playing RPGs. I can still vividly recall some of the adventures my friends and I had playing, first, Champions , and, later, Marvel Super Heroes. I remember, too, when we started to see big budget Hollywood movies featuring various costumed characters, starting with Tim Burton's Batman. The release of that movie in 1989 was a major cultural event and its success not only spawned three sequels but also paved the way for yet more superhero movies, a trend that has continued to the present day.
Despite not calling myself a fan of superheroes, I've seen more than my fair share of the superhero movies released in the last three decades, enjoying some more than others. One of the things that's always bugged me about these movies (and other adaptations) is how many of them continue to tread the same ground that their original source material did decades ago. There may indeed be nothing new under the sun, but did we really need to see another version of "The Dark Phoenix Saga?" For that matter, have there been any new superheroes or superhero stories produced in the last couple of decades with any staying power? Why are the biggest pop cultural characters all products of the 1980s or earlier?
I think about this often, most recently during a recent trip with my family. While perusing some weird snacks and candies in a store, I spied a tall, thin, red can featuring what looked to me like Larry Elmore's iconic cover painting for the Frank Mentzer-edited Dungeons & Dragons Basic Set (1984). Drawing closer, it turned that, yes, it was Elmore's artwork on a D&D-branded energy drink calling itself a "Hero's Potion of Power." Intrigued, I bought the thing, but I didn't have the courage to try it. That job fell to my daughter, who declared it "alright, but nothing special." 
On the same trip, we went to a bookstore not far from where I grew up. I hadn't found anything to purchase, so I stood out near the lobby of the store while my daughter paid for a book. When I looked over at the checkout counter, I saw a display filled with little boxes sporting an immediately recognizable color scheme. I did an almost comical double take, because I was sure that my aging eyes must have erred in some way, because I couldn't conceive that I was seeing what I, in fact, was seeing – the familiar blue and brown palette of the AD&D Monster Manual.
Sure enough, that's exactly what it was. Apparently, the boxes contain one of a series of randomized plastic monster figurines based on the illustrations of the original Monster Manual. This, frankly, befuddled me almost as much as the Hero's Potion of Power, but then I've never really understood the appeal of these expensive, randomized "loot boxes." Beyond that, why were the figurines based on the artwork of Dave Trampier and Dave Sutherland rather than more contemporary designs? Did it have something to do with D&D's 50th anniversary? I'm honestly not sure of the answer. For all I know, there may be similar loot boxes available for the monsters of later D&D editions, but my gut tells me that's unlikely to be the case. (If I'm mistaken about this, feel free to correct me in the comments).
Of course, this past Christmas, my wife bought me a Dungeons & Dragons T-shirt that she unexpectedly came across while shopping. She knows I'm normally not a wearer of such things – I abhor the brandification of the game – but the fact that the shirt featured the Erol Otus cover painting of Tom Moldvay's Basic Set was sufficiently unusual that she decided to take a chance. She was right to do so, because I was positively tickled by the gift and often wear it as a sleep shirt (I'd never wear it while out and about – I'm too old for that sort of thing).
I can't help but wonder why it is that, in the pop cultural sphere, so much of what is being presented and sold to us are the products of earlier generations of creative minds. Is this simply the result of a lack of imagination or is it because, on some level, we know that we'll never be able to come up with anything better than our predecessors? If I were to travel back in time to tell my younger self that, decades from now, there'd still be new Star Trek shows and Star Wars movies – or that I couldn't care less about any of them – I doubt he'd believe me and yet here we are. Nostalgia is a hell of a drug, but what does it mean when popular culture spends decades luxuriating in it? 
I'm as happy as anyone to see Erol Otus art on a T-shirt (even if he's unlikely to have profited from it in any way). At the same time, I think there's something not just decadent but even stagnant about endlessly recycling the pop culture of the 50s, 60, 70s, and 80s only even more vapid and rampantly consumerist than before. Have we simply run out of new ideas? Or do the new ideas simply lack the appeal of the older ones? What's really going on here and what does it mean?