Still, you can always just switch in a pokemon you consider a good Ditto counter (including the risk of letting the opponent know about its set). And if you do not have such a pokemon, it's your fault. After all, it's kinda like when two Trickscarfers meet: Of course, the first to switch out risks getting something scarfed, but then again, he can just switch in a sweeper that doesn't mind. The only exception would be that Trickscarf duels cannot be longer than 32 rounds (afaik), but I've never seen one with more than 3 rounds tbh.Using Transform isn't always the worse option.
e.g. one player uses Transform, the other one switches to let's say Blissey.
The player choosing Transform gets to scout Blisseys entire moveset, which can prove to be pivotal (does it carry seismic toss or ice beam or maybe even another damaging move? is it a pure support variant? does it carry toxic or t-wave? etc.)
And if people WANT to spend all day facing each other in a pokemon battle, there are some other options to force situations with limitless PP.