It has been suggested that this feature was changed because it failed under test, leaving balls trapped on the ring. We asked designer John Trudeau about it. He clarifies:

The original ring and [software] program were only used on the prototypes and sample games. Nothing ever failed and all the games worked flawlessly, throughout their stays at their test locations. Even the sample games sent to Europe worked well.

The problem was with the German distributor. He said he saw a potential for failure with the ball crane. In other words, he just didn't like it. I don't know why. And I never actually heard what he threatened Williams with, but it was enough pressure to have the game changed. I fought the good fight for keeping it the way it was, but I didn't have big enough clout to outweigh the potential loss of sales. So I swallowed what pride I had left and changed it. It wasn't as cool as having the balls in orbit, but there was a lot of game still there to have fun with.

The same potential "failure lock-up" point is at ANY ball popper or even the outhole. It just never made any sense to me.

The prototype games were all retrofitted with a new ring and program. The distributors were all sent conversion kits to refit their sample games to the modified play. Whether these kits ever actually found their way onto the sample games was up to the distributors. The incentive for the distributors to do the conversion was the fact that any subsequent software updates would have the "new" ring in mind. The "old" ring would only work with that original software release. I would expect that everyone would eventually do the mod.