I don't think the inventors actually thought they had samples of a superconductor for 24 years. My understanding is that they thought they'd detected signs tha

I don't think the inventors actually thought they had samples of a superconductor for 24 years. My understanding is that they thought they'd detected signs that LK-99 would be superconducting, if they were able to come up with a process to synthesize it with sufficient purity. They spent 24 years (slowly, and without a lot of funding) trying to do that. And over the last couple of years, they started to convince themselves that they had succeeded.