That's still going on in a game called Pokemon (TCG). You have $5 for a Booster Pack and you get a some cards, not knowing what's inside. I'm guessing the adrenaline of mystery is what's catching everyone.
There's lot of collectible card games (CCGs) that use that model. Truth is, they do have a fixed distribution of rare, uncommon and common cards within each booster pack. But there's never a guarantee about how useful in the game or valuable in the aftermarket that rare card happens to be.
Some companies have switched to a "Living Card Game" (LCG) model, where you buy a complete set of cards in an expansion or base set all at once, insuring you have all the cards all at once. It's not a bad model, really.
And it has NOTHING to do with the Mystery deck!
If you folks would like to continue this discussion, perhaps the Talk Park would be a good place to take it.