If you don't pay for the yearly updates, the stand-alone gps units still works (with outdated maps) However, if you don't pay the $10 monthly subscription, shall the app work? I don't think so.
Along with outdated maps, you also don't have live traffic information and automatic live traffic re-routing. NONE of the one-time payment iphone nav apps come with live traffic information and automatic live traffic re-routing.
Reality is a lot more complex than just "onetime payment good, subscription fees bad".