50,000 years is a lot of time skips unless the story is really, really long!
Is the lead immortal? Perhaps a god? Telling a bunch of stories about a god trying to keep up with humans as technology advances could be fun.
Deity: What is this stuff?
Human: We call it 'writing'
Deity: Hrm. So what else has changed in the last few thousand years?
Human: Err, I'm not sure. I've only been alive for twenty years.
Deity: Follow me then, by good friend, it's time for adventure! You can write what I do with these 'letters', right?
Human: Yes. I can, but I need clay, and a fire to harden it after.
And so on, every couple thousand years.
((yes, I know people couldn't write 50k years ago. Neanderthals were still around that long ago ))