BRK has a minimum damage
meanwhile 
meanwhile 
BOTRK requires constant attacks to proc. Liandries is a DoT.
meanwhile magic damage is still 100 times better than physical
mages just dont need that liandry so much, they cant get rekt so hard by defensive itemization since mr items give less stats and are harder to obtain
owerall it is meant to be like that, mages get to do magic damage and htis is their biggest atribute, and riot ballances magic damage to keep it as such
liandriels has a minimum damage of 1, but thx to mr it often shows 0(vs any target with >100mr after pen)
Warren Buffett has nothing to do with LoL >.>