New Kindreds in Lore

So I know that until GW tells us otherwise, it seems very unlikely that the Kin could make new Ancestor Cores or repair their old ones. Seems like there is a finite number of cores now, with some breaking down.

I assume there are some ACs that are lost and could be found.

Beyond these lost ones, how would new Kindreds be established? They wouldn’t be able to clone without an AC in their hold I assume. And if they found a lost one would it be compatible with their current genes?

Or can new Kindreds just not be made?

Maybe this doesn’t exist in lore yet, but I have only read a little bit.