This is true. The statistical probability of a vaccinated dog contracting rabies is small enough, taking it one step further, that dog contracting rabies immediately before import to Taiwan? The quarantine for rabies is a huge load of shite, and making money is definitely being had. The UK finally adopted the PETS program to allow for quarantine-less pet travel because the residents there wanted to travel to Europe and America with their pets and it became clear that rabies is not as big of a concern as it used to be. The requirements to get your dog or cat certified for PETS is about the same for getting your dog/cat imported to Taiwan!
I don’t have as much of a problem with the 21 day quarantine as I do with the 6 month waiting period after the rabies titer. This requirement is the most asinine of them all. If your dog has been vaccinated and the antibody level is high, then your dog is vaccinated! They make you wait 6 months (often meaning you leave Fido behind with family or friends) for no reason at all. They most certainly don’t retest your dog here, and for that matter, if they did, all they would do is re-vaccinate if the antibody level came back too low. This, in and of itself, is pointless because this is a rabies free island, if the dog gets here and doesn’t have rabies…then what the hell is the worry about rabies vaccination for!
I don’t see Taiwan loosening their stance on quarantine any time soon. The requirements for this import/export process come from the French run World Organisation for Animal Health (OIE). When you consider France’s love of irritating everyone in the world and Taiwan’s love of regulations and protocols, this gravy train is going to continue for a long time to come! 
In a slight defense of this process, Asia is the hotbed for rabies in the world, especially in India and China, so If you start to allow pets to go in and out of the country too easily, the next thing you know rabies or some other bad disease sneaks through customs. The quarantine is technically for rabies, but they are observing all the health aspects of your pet to make sure it is in fact a healthy animal.