Here is a wonderful article with researched answers to this painful question. http://confluence.gallatin.nyu.edu/se...
The key paragraph with the answer, in my opinion, is this:
"Immigrants often struggle with finding a job in their new country for three major reasons: the degrees and licenses they earned back home are no longer valid; they have very little disposable income; and their knowledge of English is sometimes limited. Starting a business is usually one of the only options an immigrant has, and this pattern can be easily seen around our own city, with deli-markets owned by Koreans or cabs driven by immigrants from the Caribbean, India, Bangladesh, and Pakistan. Specifically though, there is a long history of immigrants in the food industry because cooking requires little mastery of the English language and is often a trade people already know (Ray 2013). But because of Filipino’s status as “American nationals,” much of the professional training they receive in the Philippines is valid in the United States and, statistically-speaking, Filipinos have a better handle on English than many other Asian immigrant groups (Bayor 2011). With such a professional upper-hand, maybe taking a gamble on a small restaurant business seems foolish to many Filipinos."
Contrast this to the history of Chinese-American restaurants: http://www.slate.com/articles/life/fo...