Well if you drop the weapon it is on the ground and anyone, including enemies, can use their interact to pick it up (or for that matter kick it across the battlefield).
I mean if they want to switch back to the weapon, walk over to it, use their free interact to pick it up and then use it. But if you dropped it on one side of the battlefield it is there. Also the note the whole dropping a weapon thing was a big benefit for Eldritch Knights because of how they could summon it again. If you let any character do that from the other side of the battlefield ..... well that really is not supported by the rules and nerfs one of the main benefits of that subclass.
In most of my 5E martial builds I regularly drop weapons ... but if I do that they are where I dropped them and not on my belt.