Where did you get that "(years!)" from? Is it just a conclusion you came to or are those actual facts. If so, I would love to see a source or a direction to where to look for it.
The 99 in the name comes from the date the lab was formed, 1999. Some sources suggest that they have been studying this exact material since 1999, although I don't think that is confirmed.
I think it's safe to assume that they would have been making it for at least 1-2 years before the rejected Nature paper, although potentially significantly longer than that.
So they have been making it somewhere between 4 and 24 years...
Looking at how small the fragments are that other lambs are creating, I assume it's taken them years to get to the point that they can make larger lumps of the stuff that have any sort of uniform structure.
They seem to have been trying to perfect it before publishing.
> The name of the material comes from the initials of the surnames of two of the scientists — Sukbae Lee and Ji-Hoon Kim — and the year 1999, when they say they first synthesized LK-99.
https://www.nytimes.com/2023/08/03/science/lk-99-superconduc...
If I baked a cake once 23 years ago and once yesterday, I can't really say I've been baking for 23 years.
It’s called LK-99 as it was discovered in 1999.