Yea, but considering the item in question is a card you can insert in a shield's socket, that makes you 100% immune to magic, It's probally a good thing the drop rate is so low. MVP cards are so powerful, I want the Golden Thief Bug Card so bad myself.
All cards have the same drop rate really, but the thing is, only one boss(MvP) can be on the map at a time, and you have to wait an hour before it respawns.
With reg enemies, 1/10000 Isn't that bad(unless we're talking about Alice who has a special spawn rate, better then MVPs, and mini bosses, but still very low), because most enemies come in mobs
for easy enemies, you could probally get dozens ain a single day, for harder enemies, atleast 1 a month(playing only a few hours a day), unless you get very unlucky.