Why are financial instruments going to remain exclusive to the elite any more than prior revolutionary economic technologies like agriculture, refrigeration, or

Why are financial instruments going to remain exclusive to the elite any more than prior revolutionary economic technologies like agriculture, refrigeration, or pasteurization? Financial instruments in general have undergone prolonged cost decreases that don't look to be anywhere near exhausted. Patents restrict access for a couple of decades at most. If the enabling technology is affordable and patents are expired, I see no reason that financial instrument use cannot become widespread. "Not dying of poverty in childhood" was never a luxury of the elite, and it always ossified into a permanent class marker.