A thousand years without needing any change in hardware, this means that the refining technology for illusory crystals, they would struggle to reach that level even after a thousand years of research on this side.
Even though this is just an estimate, a technical breakthrough might enable them to rapidly enhance the refining technology for illusory crystals, producing crystals of the same specifications in a short period...
But that depends on luck, with good luck a genius appears and a technological breakthrough happens, with bad luck, not to mention a thousand years, even a longer period might not suffice.
This kind of technology surpasses the era and becomes strong evidence proving the intelligence.
Being ahead for ten or twenty years might be understandable, but leading by a thousand years in refining a single material?
This must be extraterrestrial beings, right?
No processing of other materials, maybe because they look down upon them.
