This is an interesting question! Maintaining this claim seems crazy. One interpretation is that Taiwan sees this as a bargaining chip with China, to be given

This is an interesting question! Maintaining this claim seems crazy. One interpretation is that Taiwan sees this as a bargaining chip with China, to be given up at an opportune moment, in exchange for something else, e.g. the China accepting Taiwan's independence. However, more likely is that giving up on the claim to rule China, might trigger the China's anti-secession laws, which in turn would lead to an invasion on Taiwan.