You can always argue that we know more now, that there are fundamental limits, etc., but there’s always more to learn and revise.
Instead, many things that seemed possible 50-150 years ago have turned out in the meantime to be impossible - speeds faster than c (before Maxwell's equations and SR), arbitrary precision measurements (before Heisenberg's uncertainty principle), uniquely determining the future state of a system based on a previous state (before wave functions), arbitrary amounts of matter and energy (before quantization of these and other properties) etc.
The history of physics is usually one of discovering new constraints, not one of discovering new possibilities. Before physics, we used to believe in unconstrained magic. Not only have we always believed we can reach the stars, we used to believe we could do it by finding the right magical formula or praying hard enough.
Of course there are some exceptions - electricity and quantum computing come to mind.
5000 years is before Ozymandias. Look on my works, ye Mighty, and despair!