Put it this way - javelin throwers would have a really hard time hitting individual targets if they were using their skills in anger.
Compare this with a cricket fielder going for a run out. Usually he's moving at pace, has to reach to the ground and pick up the ball which is also moving at pace, and then take a shot at a few slivers of wood at an acute angle under severe time pressure. They don't always hit the target but they can be extremely accurate.
(Cue gratuitous 1990s cricket clips featuring Jonty Rhodes below.)
What I'm trying to get at is: accurate throwing is a matter of chucking small dense items at stationary targets. A cricketer has a reasonable chance of hitting the stumps because they're not moving.
Does it make sense to say that thrown objects in D&D only hit if the target is stationary, i.e. surprised? Perhaps not - we've all been in the situation as a kid where your friend is about to throw something at you from a few paces away and you know that you're likely to be hit however much you might duck and dive. But it might make sense to come up with a thrown object house rule:
Thrown Objects House Rule
Standard ranges for thrown objects/weapons only apply where the target is stationary. Otherwise, the effective range of all thrown objects is 5 yards.