Without such a guarantee, they won't even want to invest in Taiwan because they will be afraid they won't be able to sell their products in other countries, or won't be able to compete because of high tariffs, which would be a dead-end street for them.
如果沒有這個保障，業者恐怕連在國內投資都不想，因為怕投資後的產品賣不出去，或者關稅太高沒辦法競爭，那業者等於死路一條啊！