Tell someone in the 1600s about the concept of cellphones and they would say it’s impossible to ever instantaneously communicate with someone around the world.
It’s so energy intensive with our current technology, which isn’t really an answer to fermi.
I don't know that they would.
In the 1600s, they'd just invented the printing press, so communication was already undergoing a fairly massive change. A book that once took a lifetime to copy could now be printed in three days.
From there, it's a short walk to "this book that used to take a lifetime to copy can now be printed more or less instantly." And from there, we can start laying the groundwork for what we would eventually call telecommunications.
Cell phones rely on technology that people in the 1600s hadn't discovered yet. Interstellar travel would require us to not only discover new technologies, but technologies that actively violate what seem to be pretty hard physical laws.
If the speed of light really is a universal maximum, and something like an Alcubierre warp drive isn't possible, leaving this solar system is vanishingly unlikely.
You say that they saw books get printed faster, so they could conceive communication getting so fast it’s instant, despite their knowledge being limited to physical material.
By the same logic, couldn’t I say we have theorized wormholes and have already seen objects (like black holes) warp time and space? Therefore maybe we can warp space to travel, rather than literally needing to go faster than light?
I think it’s easier for us now to conceive the idea that one day we could make a wormhole than it is for people with no concept of radio waves to conceive the idea of a cellphone.
Plenty of empires (e.g. the Byzantines) had chains of fire signal towers (IIRC some had mirror signal towers). That's not instant, but it shrinks weeks of delay down to an hour, albeit with just half a bit of information. And the concept of going up a sufficiently tall mountain and being able to see a signal on the other side of the world is comprehensible to basically anyone (it's not physically possible, but they didn't necessarily know that).