I find that a very common concept in fantasy fiction is the fact that human (I am using the word to also include humanoids) acchievements are decreasing over time. Usually, some sort of glorious remains of days in which people were capable of gread deeds remain, but only as ruins or artifacts of some sort. A few examples I came across:
- LOTR: in ancient times, elves were able to stand up to Morgoth with a whole army of balrogs. In fact, a single elf was able to stand his ground in a fight against Morgoth. At the time the storry occurs, however, a Maia (Gandalf) dies while fighting a balrog, which in olden days would be just one of several in an army. Sauron, a being of far lesser power than Morgoth, almost enslaves the whole of Middle Earth. No human, or elf, for that matter, can hope to oppose him alone. In fact, even the humans degraded from ancient times, with Aragorn being some sort of relic. Even at the end, when "all is well", the might of the human kingdom is a shadow of what Numenor's power.
- GoT: In times past, humans built the wall. They had dragons, and fire mages and all sorts of stuff that is now only a part of legends. Ancient artifacts (like that what's-it-called horn) carry great power because they are remnants of a time when humanity was capable of much greater feats.
- Star Wars: The lates (episodes 4,5,6) war agains the sith is really nothing compared to the first great hiperspace wars. Going even further back, the Rakata empire was way way way more powerful than anything seen in the movies.
- D&D: Artifacts from ancient Netheril are among the most dangerous things in the world, because they hold the key to the power that was, once, wielded every day. Even further back, the power of the Creator Races makes even the Netherese seem puny in comparison.
- Elder scrolls: Both the Ayleids and the Dwemer were, in ancient times, capable of great feats that have no match in modern times.
There are even more examples, like Warcraft (ancient Night elves), I could probably think of. What's more, I can't think of one fantasy world where the most awesome things are happening at the time of the story.
Why is this the case? Is this pandering to the fact that humans like to complain and think oh, in the olden days, thigs were so much better!" That seems the obvious answer, but I think many authors realize that for the vast majority of times, children in the real world lived better, longer and happier times than their parents (with some steep drops, sure, but the average is rising). Any ideas?