About 65% of the TW3 (EVA, China Airlines, Starlux) TPAC traffic is transit in Taipei so take that into consideration when you think about UA doing more new TPAC routes to TPE. In general, the Taiwanese prefer Taiwanese carriers - the service, the food, the language. Companies in Taiwan tend to be very competitive with each other - just look at how many convenience stores and bubble tea shops in Taiwan.