You made good points, but I hold a different opinion on your first point. Although many products made in other countries, especially those produced in Asian countries like Vietnam and India, are cheaper than domestically produced goods, many of them are inferior goods. It means that consumers consume those products less frequently as their income increases; Clothes with plain design and cheap clothing materials are typical examples. Those prevailing consumer goods are often provided at a relatively high price like designer clothes and high-tech goods. In a nutshell, domestic people are spending more on the goods that they didn't feel a need to buy before International trade; Namely, International trade doesn't help people to save money.

International trade would make less-developed countries struggled for development. Less-developed countries in International trade are famous for their high labor supply while being less competitive in the high tech area. The incubation of many modern high-tech industries is quite capital-intensive. The threshold of entry is usually high regarding the need for funding, intelligent human capital, time, and etc. From the world scale, there must be a comparatively advanced leader and other competing countries. If there’s no interference like trade barriers, the business in the leading position could easily knock down any late-bloomer owing to the economies of scale that the leader has already achieved. The example of Baidu could be illustrated here. Google was far ahead of any competitors within the browser area when Baidu was founded. Though the deliberate interference from the Chinese government seemed unethical, Baidu was apparently benefitted. The job opportunities that brought later by Baidu and the boost of related industries were exactly the aftermath of the protective practice. In a nutshell, international trade could inhibit economic growth and technological breakthrough, hurting less-developed countries.