> it would have been very hard for them to imagine the direction that _technology_ would go. That writing (scrolls and ink) could expand into something like the internet and smartphones

Our reality has already vastly surpassed main stream sci fi of only fifty years ago.

> could there be something two thousand years from now that is practically unimaginable to us?

It's less likely because to be unimaginable it would have to be based on undiscovered physics which is less likely now than it was even just a few hundred years ago.

I think the primary reason why our reality has quickly surpassed a bulk of earlier sci-fi is that sci-fi starts to become less interesting on average as AIs/robots start to dominate the frontier of everything.

It's "progress" but it's...not interesting except at the beginning of the threshold, when AIs overtake humanity. In many sci-fi stories that's a dominant theme, but it's not likely to be a long epoch in reality IMO, based on the very brief periods when machines/AIs have overtaken humans in individual domains (arithmetic, chess, Go, coding, translation, CGI, etc).