Why can't you use adhesive magnetic strips/tape on the outside of the iPad 1? Sure, it may be slightly unsightly, but it should be completely workable. Heck, the strip doesn't even have to be magnetic, it can be paramagnetic or such and just channel field between magnets on the cover hinge.
The downvotes you've gotten aren't fair but it's worth pointing out:
It's this kind of thinking (on the part of their competition) that lets Apple keep their head start for way, way longer than necessary.
The short answer: Because what you're proposing would be terrible.
Apple's money magnet is creating a sense of delight and surprise. You'd be mimicking the result, a snap on cover, without grasping the intent, which is to make you feel like a kid seeing magic. People don't want a cover. They want to be delighted by a cover.
At least, they do now, since Apple has shown them it is possible to feel this way.
Yay! Throw the iPad 1 in the trash for the iPad 2! Because the cover is blinged out with a magnet! On. the. inside! MAGNETS ARE MAGIC! Watch the magician make your money disappear into his pocket! Waste! Waste! Waste! This country is doomed.
