it should have been outlawed from day one.
Agreed, but I keep thinking if belly putters were so wonderful and gave the player such a big advantage, why hasn't all the money players adopted it?
It's hard to say there's an uneven playing field as long as everyone plays by the same rules. The rules are obviously arbitrary, and any player can do what works best for themselves within the rules. A perceived advantage is not an unfair advantage if it is available to everyone. But the rules may also be amended or clarified over time to reflect the spirit or even just the aesthetics of the game. So I say good riddance to the belly putter.
Plus, the rules already prohibit the fun trick of holing a short putt using the handle of the putter like a pool cue. Fun but in poor taste.
By the same token, I think they should have banned the over-sized tennis rackets as soon as they appeared, or they should have had a rule in place to define how large the head of the racket can be. So the "normal" sized racket I learned with became obsolete overnight and it is a zero-sum game if everyone got the big racket. I just think the big racket is cheesy. It's a question of aesthetics more than sportsmanship.