Does thin lube wear out or disintegrate over time or is the only way to get rid of it by cleaning the bearing?
The bearing will break in after a while. This will cause the responsive properties of the lube to diminish. So in short, yes it will wear out.
Edit - but if you want to “get rid of it” the you’d have to clean the bearing.
Sweet 
it completely fixed the vibe but reduced my spin time a bit, never used lube so thanks
Liquid lube is viscus, it does not “break in” it just gets pushed away enough to allow free unresponsive play for a while.
Wouldn’t break down as it is used up?
I believe that eventually lube will break down but how long that takes all depends on what it is composed of. I think that before it breaks down though you would be replacing it with new lube since as you play it picks up some debris and you would notice this before it broke down physically.