It is ignorant to say that one is poor because one is lazy and not trying to be not poor. Because being poor is not only an individual problem but it also points to the failure of the social system in which those individuals live.

And to say that those chinese immigrants and their offsprings generally are more hard-working than local Thais, hence they are richer, are also not smart. In the past thai social system was feudal. There was no middle class but only ruling class which included kings, HM families, and noblemen or bureaucrats; and peasants. And those who were neither were classified as slaves.

Being peasants at that time could not be much better than being slaves given that, although, they were considered human beings but their existence depended on ruling class to whom they were employed and serviced. Not to mention one type of peasants who were conscripted to work for kings and HM families every other month and struggled to make end meet when they were free of "royal" duties.

On the contrary, the Chinese immigrants were regarded as outliers or pariahs, therefore, they were not included in this system. But they must do something productive to the country for exchange. Since becoming noblemen or bureaucrats were out of questions, they then elected to be traders and merchants. Overtime, they took hold of this country economy especially after the period when Siam (was forced to) agreed to sign free trade treaty with Great Britain. And when the feudal system collapsed, local Thais became unskilled labors and fled to work in agricultural field. And those who already prospered from tradeing became richer. So the root cause of local Thais being poorer than chinese immigrants and their offspring, are much more complex than the authors of this article has led us to believe.