What Makes An Ilocano?

Any everyday man in the Philippines would associate an Ilocano with a one word description - "matipid", on extremes, kuripot - okay, English sounds better - frugal. We are known to be hard workers and success achievers. We never identify to the words "difficult and failure".
I have been researching what keeps the Ilocano apart for him to earn this description. The only reason I could think of is the means of livelihood that was adapted by the forerunners in the Ilocos region. Most if not all of the Ilocos region descendants were tobacco growers (kitaen yo kadi itti litrato ni Manang Biday nakaam-mel itti tabako). Tobacco was the main agricultural product for this was a good match to the type of soil Ilocos has. This region is surrounded by the Cordilleras and most of its land is rocky and arid.
Another reason why tobacco was a prevalent crop then was the tobacco monopoly during the Spanish times. If we all recall our History classes then, tobacco growing was encouraged if not forced upon by the Spaniards to the Filipinos to sustain the revenue this crop generates. In so doing, the Philippine colony then was not totally dependent on Spain for financial sustenance. Early on. the Spaniards recognized that the revenue generated from tobacco will be more than enough for the Philippine Colony to use.( colony - such an awful word then and now).
The Ilocano then, has been used to tilling the soil under the sweltering sun. That could be the reasons for our skin attributes. But why the adjectives kuripot, matipid or frugal though? I still can not put my finger to the reason why. Maybe some of you do know.