With the recently-added "weapon proficiency affecting upkeep cost", this additional requirement needs to go away. If I want to pay huge repair bills and not be able to hit anything more than 3 ft away, I should be able to have 10 PT and 1 throwing wpf and still be able to pick up throwing weapons.
Poor proficiency with a weapon should increase the chance that you break it. That's realistic and balanced.
It shouldn't prevent me from being able to reach down and pick one up.