I am not sure why you would make this implication about ESL. Some students may well be bilingual but many others have not knowledge of English, whether spoken or written.
My response to you regarded the acronyms that float in cyber space. ESL, EFL, TOEFL, and many others are just acronyms that encompass the same basic methodology and pedagogical ideas. Discussion about the differences in each will not lead to changes in the methodology and as teachers, this is where our professionalism is grounded.
I certainly agree, based on my experience, that Chinese employers may not know what the acronyms mean or stand for. Their goal is to fill the requirement of teaching English. So perhaps this begs the question about why they seek "native speakers" of English. The long discussions previously about trained educators versus a warm body that can speak English is not the purpose of this response. However, it does highlight the term "scholars" from the Philippines. One of the reasons these scholars may not be held in high regard professionally is because of the less than rigorous requirements within the Philippine higher education system.
The only exception to your response would be the term "mammoth" difference. If you cannot demonstrate this difference, perhaps others here can respond with these differences?