I can't say I've ever had a pickup die on me other than I've had one go bad where the wire of the winding itself got a break in it somehow due to oxidation. It was a very old single coil. The other weird thing I've seen is a freind of mine who brought his Strat to where he worked, and he stowed it near a large electrical motor and the emf field deguassed the pickups or in simple terms it demagnetized the pickups, which ain't a good thing.
Did the tech ever tell you why your pickup went bad? I'm also curious as to why both coils would be bad scince your P-Bass has the standard split coil pickup. Both halves are wired up like a humbucker and to have a general volume loss on both coils does seem weird to me. At least your warranty is saving the day. I hope your bass comes back better than ever.