The difference is one is cheap production, based on a design by the real BL, made to be as profitable as possible. The other is literally a boutique pickup, made by its inventor, with no regard to anything but quality - BECAUSE HIS NAME IS ON IT.
You do realize, that for the real BL to sell, direct only, not through dealers.... there is no extra markup. If the real BL pickups were sold through dealers, you'd be paying at least 50 percent more. In effect, he's a small shop, makes his stuff, employs only a few folks, and sells what he can - and lets his inventions pay the payroll, rent, lights, and groceries. SuperHumbucker - his. Blade design pickups - his. Noiseless pickups for Fender - his. Gibson P-100 pickup (and all stacked humbuckers) - his. Offset coil pickups - his. Cross type magnetic circuit - his. Lower impedance, but high output pickups - his. Use of inductors in a variable circuit for tone control in a guitar - his. And the list goes on and on.