I’d like to know a bit more about the cost involved and who will end up paying for all this. I can imagine this to be a financial and logistical challenge at Taoyuan International Airport where there are currently two very old Terminals, one from which China Airlines and their SkyTeam partners such as Delta operate. Then another one for EVA Air and Star Alliance.
Both terminals are definitely coming into their years but not only that, having a pre-clearance facility there means that all airlines should use it in order to make it worthwhile.
This means the airport needs to designate one part of the terminal (or build a new one) for U.S. departures which is sealed off past the U.S. Immigration checkpoint.