It's not that it's more difficult to do, it's that you generally don't do it. SCOTUS in particular will not respond to, mention, or address anything even approaching a hypothetical scenario, which is sometimes frustrating when the specifics of a case aren't just ride for larger sweeping changes that society may want. You'll often hear of proponents of one reform or another saying that a given case is perfect for SCOTUS because it lines up very closely with their policy objectives.