Faerun has had a couple of loosely defined ages. The most recent one is the Age of Humanity, which doesn’t line up with the Dale Reckoning at all for some reason. The Age of Humanity begins with the rise of the ancient Netherese Empire, the first really big-deal human nation, and is ongoing today, even though Netheril collapsed nearly two thousand years ago. All told it’s four and a half thousand years of time. It’s mostly empty. Between -3000 DR and 0-year, basically the only thing that happens is that Netheril is a thing and the Old Empires establish themselves. Three thousand years just so that one empire can rise and fall (the Roman Empire lasted 2000 years in even the most extreme interpretations, and if we’re more strict about ruling out enclaves and successor states, they lasted more like 1000) and some of the older nations can have their origin stories before the newer ones. We don’t need 3000 years for that. We need like five centuries.
This is not the most egregious waste of space on the timeline, though. The Crown Wars occurred between -12000 DR and -9000 DR. There are five Crown Wars. I summed up the entirety of their events in a single blog post. Even if each one required a full 100 years recovery period for a new generation of elven warriors to be raised, we’re still talking about a couple of centuries. What did they do for three thousand years?
That’s not the most egregious waste of space on the timeline, though. The very first age was when five ancient civilizations all emerged from the primordial gloop from -25000 DR to -20000 DR and just sort of…existed for five thousand years. The era of the sarrukhs and company has almost zero actual events or stories in it, just these civilizations existing, and it takes up 5000 years on the timeline. Could’ve gotten away with 1000, tops, and that only because you need civilizations to both rise and fall in that time span.
That’s not the most egregious waste of space on the timeline, though. The most egregious waste of space on the timeline is the First Founding. This is the time from -9000 DR to -3000 DR when dwarves and elves did nothing for six thousand years. It wasn’t the first founding of anything in particular, since elves had been around for millennia and so had dwarves. There’s just this big six thousand year gap in the timeline labeled “the First Founding” for no reason. Just to have more space in between the height of elven civilization and the modern day, I guess.
Fantasy authors have a perception of time that’s as jacked up as a sci-fi writer’s perception of distance.