definitely once ruins run out, buy gold over cultist (read: lab-bm is entirely not a thing) as well as when you don't think you would be able to play the cultist before ruins become empty (i.e., the beginning of the shuffle). indeed, none of these things matter and cultist games are just not fun if there isn't much of another thing, and the emotional effect of buying cultists probably outweighs the strategical one at some point.
