Not sure why this is even being discussed...

Stern makes the Pro for Route Operators. Best bang for the buck and no competitors in the same price range.
Stern makes the LE version for the home collectors. The same home collectors who paid a lot for Metallica LE when it was released and in short supply, and (some would argue) drove up the price.
Personally, my preference is the Premium model.
I was annoyed when I heard that Stern wouldn't be making a Premium version for every new title at first, but then it occurred to me: they're only going to run Premium versions if they think there will be a big demand for them.

At the end of the day, this is best for everyone. Ops can buy cheaper versions for their route. Collectors can buy pins without full code, and sit on them until that code has been completed, hoping it will turn out. If it's great, their purchase may go up in value. They are taking a risk though so hopefully they're fans on the theme and not just speculators.
The last option is more my speed: once the code is well developed, and the game is a hit, Stern announces a Premium version and I get to buy one.

By not running a Premium for every model, they protect the distributors and they protect themselves. If a title is a dud, who can afford to sit on even a few of these things when the profit margin is so slim?

Lastly, regarding your comments about how the Pro should have all the playability of the LE...
Quit your whining. A "full" pinball costs more than the Pro model. If you have a "Pro budget", you should be happy to have the opportunity to be able to get a NIB pin at all. Besides, if the Pro played the same as the LE, how would Stern justify charging an extra $2000+?