OK, but a function that's been broken FOR YEARS seems a bit like it should be fixed... right? It's really frustrating when we go around in circles like this and the only response is "it's been broken for years (and may be broken for many more years, we can't say)."
This doesn't engender a feeling in your customers that you are committed to fixing problems before rolling out new (potentially broken or not completely formed) features, and that lack of quality and commitment drives customers to other vendors.