I predict an absolute maximum of Ten Years before a writer or writers retcons it into her lying about little Helena being Bruce's (Like she wouldn't?) and brings her back in, barring larger continuity reboots (that we desperately need) and even in CASE of larger continuity reboots, we're still probably gonna get it.
...This also assuming that a certain figure in Whatever Happened To The Caped Crusader isn't Helena of either Earth-2 or this Helena in some form, which is a working theory of mine. If spoilers have already proved me wrong,